https://www.math.wisc.edu/wiki/api.php?action=feedcontributions&user=Craciun&feedformat=atomUW-Math Wiki - User contributions [en]2020-08-04T12:08:50ZUser contributionsMediaWiki 1.30.1https://www.math.wisc.edu/wiki/index.php?title=Colloquia&diff=17781Colloquia2019-09-07T02:59:42Z<p>Craciun: </p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Fall 2019==<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| Jianfeng Lu (Duke)<br />
|[[#TBA | TBA]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 27<br />
| Omer Mermelstein (Madison)<br />
|<br />
|Andrews<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
|<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Nov 15<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Nov 22<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 6<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Dec 11 '''Wednesday'''<br />
|Nick Higham (Manchester)<br />
|LAA lecture<br />
|Brualdi<br />
|<br />
|-<br />
|Dec 13<br />
|Reserved for job talk<br />
|<br />
|}<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 24<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Jan 31<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 7<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 14<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 21<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|(Moduli Spaces Conference)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|<br />
|<br />
|<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
<br />
===Will Sawin (Columbia)===<br />
<br />
Title: On Chowla's Conjecture over F_q[T]<br />
<br />
Abstract: The Mobius function in number theory is a sequences of 1s, <br />
-1s, and 0s, which is simple to define and closely related to the <br />
prime numbers. Its behavior seems highly random. Chowla's conjecture <br />
is one precise formalization of this randomness, and has seen recent <br />
work by Matomaki, Radziwill, Tao, and Teravainen making progress on <br />
it. In joint work with Mark Shusterman, we modify this conjecture by <br />
replacing the natural numbers parameterizing this sequence with <br />
polynomials over a finite field. Under mild conditions on the finite <br />
field, we are able to prove a strong form of this conjecture. The <br />
proof is based on taking a geometric perspective on the problem, and <br />
succeeds because we are able to simplify the geometry using a trick <br />
based on the strange properties of polynomial derivatives over finite <br />
fields.<br />
<br />
<br />
===Yan Soibelman (Kansas State)===<br />
<br />
Title: Riemann-Hilbert correspondence and Fukaya categories<br />
<br />
Abstract: In this talk I am going to discuss the role of Fukaya categories in the Riemann-Hilbert correspondence<br />
for differential, q-difference and elliptic difference equations in dimension one.<br />
This approach not only gives a unified answer for several versions of the Riemann-Hilbert correspondence but also leads to a natural formulation<br />
of the non-abelian Hodge theory in dimension one. It also explains why periodic monopoles<br />
should appear as harmonic objects in this generalized non-abelian Hodge theory.<br />
All that is a part of the bigger project ``Holomorphic Floer theory",<br />
joint with Maxim Kontsevich.<br />
<br />
<br />
===Alicia Dickenstein (Buenos Aires)===<br />
<br />
Title: Algebra and geometry in the study of enzymatic cascades<br />
<br />
Abstract: In recent years, techniques from computational and real algebraic geometry have been successfully used to address mathematical challenges in systems biology. The algebraic theory of chemical reaction systems aims to understand their dynamic behavior by taking advantage of the inherent algebraic structure in the kinetic equations, and does not need the determination of the parameters a priori, which can be theoretically or practically impossible.<br />
I will give a gentle introduction to general results based on the network structure. In particular, I will describe a general framework for biological systems, called MESSI systems, that describe Modifications of type Enzyme-Substrate or Swap with Intermediates, and include many networks that model post-translational modifications of proteins inside the cell. I will also outline recent methods to address the important question of multistationarity, in particular in the study of enzymatic cascades, and will point out some of the mathematical challenges that arise from this application.<br />
<br />
<br />
<br />
<br />
===Shamgar Gurevich (Madison)===<br />
<br />
Title: Harmonic Analysis on GL(n) over Finite Fields.<br />
<br />
Abstract: There are many formulas that express interesting properties of a finite group G in terms of sums over its characters. For evaluating or estimating these sums, one of the most salient quantities to understand is the character ratio:<br />
<br />
trace(ρ(g)) / dim(ρ),<br />
<br />
for an irreducible representation ρ of G and an element g of G. For example, Diaconis and Shahshahani stated a formula of the mentioned type for analyzing certain random walks on G.<br />
<br />
Recently, we discovered that for classical groups G over finite fields there is a natural invariant of representations that provides strong information on the character ratio. We call this invariant rank. <br />
<br />
This talk will discuss the notion of rank for the group GLn over finite fields, demonstrate how it controls the character ratio, and explain how one can apply the results to verify mixing time and rate for certain random walks.<br />
<br />
This is joint work with Roger Howe (Yale and Texas AM). The numerics for this work was carried by Steve Goldstein (Madison)<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia&diff=17396Colloquia2019-04-26T17:43:16Z<p>Craciun: </p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
==Spring 2019==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Jan 25 '''Room 911'''<br />
| [http://www.users.miamioh.edu/randrib/ Beata Randrianantoanina] (Miami University Ohio) WIMAW<br />
|[[#Beata Randrianantoanina (Miami University Ohio) | Some nonlinear problems in the geometry of Banach spaces and their applications ]]<br />
| Tullia Dymarz<br />
|<br />
|-<br />
|Jan 30 '''Wednesday'''<br />
| Talk rescheduled to Feb 15<br />
|<br />
|-<br />
|Jan 31 '''Thursday'''<br />
| Talk rescheduled to Feb 13<br />
|<br />
|-<br />
|Feb 1<br />
| Talk cancelled due to weather<br />
|<br />
| <br />
|<br />
|-<br />
|Feb 5 '''Tuesday, VV 911'''<br />
| [http://www.math.tamu.edu/~alexei.poltoratski/ Alexei Poltoratski] (Texas A&M University)<br />
|[[#Alexei Poltoratski (Texas A&M)| Completeness of exponentials: Beurling-Malliavin and type problems ]]<br />
| Denisov<br />
|<br />
|-<br />
|Feb 6 '''Wednesday, room 911'''<br />
| [https://lc-tsai.github.io/ Li-Cheng Tsai] (Columbia University)<br />
|[[#Li-Cheng Tsai (Columbia University)| When particle systems meet PDEs ]]<br />
| Anderson<br />
|<br />
|-<br />
|Feb 8<br />
| [https://sites.math.northwestern.edu/~anaber/ Aaron Naber] (Northwestern)<br />
|[[#Aaron Naber (Northwestern) | A structure theory for spaces with lower Ricci curvature bounds ]]<br />
| Street<br />
|<br />
|-<br />
|Feb 11 '''Monday'''<br />
| [https://www2.bc.edu/david-treumann/materials.html David Treumann] (Boston College)<br />
|[[#David Treumann (Boston College) | Twisting things in topology and symplectic topology by pth powers ]]<br />
| Caldararu<br />
|<br />
|-<br />
| Feb 13 '''Wednesday'''<br />
| [http://www.math.tamu.edu/~dbaskin/ Dean Baskin] (Texas A&M)<br />
|[[#Dean Baskin (Texas A&M) | Radiation fields for wave equations ]]<br />
| Street<br />
<br />
|-<br />
| Feb 15 <br />
| [https://services.math.duke.edu/~pierce/ Lillian Pierce] (Duke University)<br />
| [[#Lillian Pierce (Duke University) | Short character sums ]]<br />
| Boston and Street<br />
|<br />
|-<br />
|Feb 22<br />
| [https://people.math.osu.edu/cueto.5/ Angelica Cueto] (Ohio State)<br />
|[[#Angelica Cueto (The Ohio State University)| Lines on cubic surfaces in the tropics ]]<br />
| Erman and Corey<br />
|<br />
|-<br />
|March 4 '''Monday'''<br />
| [http://www-users.math.umn.edu/~sverak/ Vladimir Sverak] (Minnesota) <br />
|[[#Vladimir Sverak (Minnesota) | Wasow lecture "PDE aspects of the Navier-Stokes equations and simpler models" ]]<br />
| Kim<br />
|<br />
|-<br />
|March 8<br />
| [https://orion.math.iastate.edu/jmccullo/index.html Jason McCullough] (Iowa State)<br />
|[[#Jason McCullough (Iowa State)| On the degrees and complexity of algebraic varieties ]]<br />
| Erman<br />
|<br />
|-<br />
|March 15<br />
| <s>[http://www.its.caltech.edu/~maksym/ Maksym Radziwill] (Caltech)</s> <b>Talk cancelled</b><br />
|[[#Maksym Radziwill (Caltech) | <s>Recent progress in multiplicative number theory</s> ]]<br />
| Marshall<br />
|<br />
|-<br />
|March 29<br />
| Jennifer Park (OSU)<br />
|[[#Jennifer Park (OSU) | Rational points on varieties ]]<br />
| Marshall<br />
|<br />
|-<br />
|April 5<br />
| Ju-Lee Kim (MIT)<br />
|[[#Ju-Lee Kim (MIT) | Types and counting automorphic forms ]]<br />
| Gurevich<br />
|<br />
|-<br />
|April 12<br />
| Eviatar Procaccia (TAMU)<br />
|[[#Eviatar Procaccia | Can one hear the shape of a random walk? ]]<br />
| Gurevich<br />
|<br />
|-<br />
|April 19<br />
| [http://www.math.rice.edu/~jkn3/ Jo Nelson] (Rice University)<br />
|[[#Jo Nelson (Rice)| Contact Invariants and Reeb Dynamics ]]<br />
| Jean-Luc<br />
|<br />
|-<br />
|April 22 '''Monday'''<br />
| [https://justinh.su Justin Hsu] (Madison)<br />
|[[#Justin Hsu (Madison) | From Couplings to Probabilistic Relational Program Logics ]]<br />
| Lempp<br />
|<br />
|-<br />
|April 26 '''Room 911'''<br />
| [https://www.brown.edu/academics/applied-mathematics/faculty/kavita-ramanan/home Kavita Ramanan] (Brown University)<br />
|[[# Kavita Ramanan (Brown) | Tales of Random Projections ]]<br />
| WIMAW<br />
|<br />
|-<br />
|May 3<br />
| Tomasz Przebinda (Oklahoma)<br />
|[[# TBA| TBA ]]<br />
| Gurevich<br />
|<br />
|}<br />
<br />
<br />
<br />
<br />
<br />
<br />
==FALL 2019==<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 13 '''Room 911'''<br />
| Alicia Dickenstein (University of Buenos Aires)<br />
|[[# TBA| TBA ]]<br />
| Gheorghe Craciun<br />
|<br />
|}<br />
<br />
<br />
<br />
== Abstracts ==<br />
<br />
===Beata Randrianantoanina (Miami University Ohio)===<br />
<br />
Title: Some nonlinear problems in the geometry of Banach spaces and their applications.<br />
<br />
Abstract: Nonlinear problems in the geometry of Banach spaces have been studied since the inception of the field. In this talk I will outline some of the history, some of modern applications, and some open directions of research. The talk will be accessible to graduate students of any field of mathematics.<br />
<br />
===Lillian Pierce (Duke University)===<br />
<br />
Title: Short character sums <br />
<br />
Abstract: A surprisingly diverse array of problems in analytic number theory have at their heart a problem of bounding (from above) an exponential sum, or its multiplicative cousin, a so-called character sum. For example, both understanding the Riemann zeta function or Dirichlet L-functions inside the critical strip, and also counting solutions to Diophantine equations via the circle method or power sieve methods, involve bounding such sums. In general, the sums of interest fall into one of two main regimes: complete sums or incomplete sums, with this latter regime including in particular “short sums.” Short sums are particularly useful, and particularly resistant to almost all known methods. In this talk, we will see what makes a sum “short,” sketch why it would be incredibly powerful to understand short sums, and discuss a curious proof from the 1950’s which is still the best way we know to bound short sums. We will end by describing new work which extends the ideas of this curious proof to bound short sums in much more general situations.<br />
<br />
===Angelica Cueto (The Ohio State University)===<br />
Title: Lines on cubic surfaces in the tropics<br />
<br />
Abstract: Since the beginning of tropical geometry, a persistent challenge has been to emulate tropical versions of classical results in algebraic geometry. The well-know statement <i>any smooth surface of degree three in P^3 contains exactly 27 lines</i> is known to be false tropically. Work of Vigeland from 2007 provides examples of tropical cubic surfaces with infinitely many lines and gives a classification of tropical lines on general smooth tropical surfaces in TP^3.<br />
<br />
In this talk I will explain how to correct this pathology by viewing the surface as a del Pezzo cubic and considering its embedding in P^44 via its anticanonical bundle. The combinatorics of the root system of type E_6 and a tropical notion of convexity will play a central role in the construction. This is joint work in progress with Anand Deopurkar.<br />
<br />
===David Treumann (Boston College)===<br />
<br />
Title: Twisting things in topology and symplectic topology by pth powers<br />
<br />
Abstract: There's an old and popular analogy between circles and finite fields. I'll describe some constructions you can make in Lagrangian Floer theory and in microlocal sheaf theory by taking this analogy extremely literally, the main ingredient is an "F-field." An F-field on a manifold M is a local system of algebraically closed fields of characteristic p. When M is symplectic, maybe an F-field should remind you of a B-field, it can be used to change the Fukaya category in about the same way. On M = S^1 times R^3, this version of the Fukaya category is related to Deligne-Lusztig theory, and I found something like a cluster structure on the Deligne-Lusztig pairing varieties by studying it. On M = S^1 times S^1, Yanki Lekili and I have found that this version of the Fukaya category is related to the equal-characteristic version of the Fargues-Fontaine curve; the relationship is homological mirror symmetry.<br />
<br />
===Dean Baskin (Texas A&M)===<br />
<br />
Title: Radiation fields for wave equations<br />
<br />
Abstract: Radiation fields are rescaled limits of solutions of wave equations near "null infinity" and capture the radiation pattern seen by a distant observer. They are intimately connected with the Fourier and Radon transforms and with scattering theory. In this talk, I will define and discuss radiation fields in a few contexts, with an emphasis on spacetimes that look flat near infinity. The main result is a connection between the asymptotic behavior of the radiation field and a family of quantum objects on an associated asymptotically hyperbolic space.<br />
<br />
===Jianfeng Lu (Duke University)===<br />
<br />
Title: Density fitting: Analysis, algorithm and applications<br />
<br />
Abstract: Density fitting considers the low-rank approximation of pair products of eigenfunctions of Hamiltonian operators. It is a very useful tool with many applications in electronic structure theory. In this talk, we will discuss estimates of upper bound of the numerical rank of the pair products of eigenfunctions. We will also introduce the interpolative separable density fitting (ISDF) algorithm, which reduces the computational scaling of the low-rank approximation and can be used for efficient algorithms for electronic structure calculations. Based on joint works with Chris Sogge, Stefan Steinerberger, Kyle Thicke, and Lexing Ying.<br />
<br />
===Alexei Poltoratski (Texas A&M)===<br />
<br />
Title: Completeness of exponentials: Beurling-Malliavin and type problems<br />
<br />
Abstract: This talk is devoted to two old problems of harmonic analysis mentioned in the title. Both<br />
problems ask when a family of complex exponentials is complete (spans) an L^2-space. The Beruling-Malliavin<br />
problem was solved in the early 1960s and I will present its classical solution along with modern generalizations<br />
and applications. I will then discuss history and recent progress in the type problem, which stood open for<br />
more than 70 years.<br />
<br />
===Li-Cheng Tsai (Columbia University)===<br />
<br />
Title: When particle systems meet PDEs<br />
<br />
Interacting particle systems are models that involve many randomly evolving agents (i.e., particles). These systems are widely used in describing real-world phenomena. In this talk we will walk through three facets of interacting particle systems, namely the law of large numbers, random fluctuations, and large deviations. Within each facet, I will explain how Partial Differential Equations (PDEs) play a role in understanding the systems.<br />
<br />
===Aaron Naber (Northwestern)===<br />
<br />
Title: A structure theory for spaces with lower Ricci curvature bounds.<br />
<br />
Abstract: One should view manifolds (M^n,g) with lower Ricci curvature bounds as being those manifolds with a well behaved analysis, a point which can be rigorously stated. It thus becomes a natural question, how well behaved or badly behaved can such spaces be? This is a nonlinear analogue to asking how degenerate can a subharmonic or plurisubharmonic function look like. In this talk we give an essentially sharp answer to this question. The talk will require little background, and our time will be spent on understanding the basic statements and examples. The work discussed is joint with Cheeger, Jiang and with Li.<br />
<br />
<br />
===Vladimir Sverak (Minnesota)===<br />
<br />
Title: PDE aspects of the Navier-Stokes equations and simpler models<br />
<br />
Abstract: Does the Navier-Stokes equation give a reasonably complete description of fluid motion? There seems to be no empirical evidence which would suggest a negative answer (in regimes which are not extreme), but from the purely mathematical point of view, the answer may not be so clear. In the lecture, I will discuss some of the possible scenarios and open problems for both the full equations and simplified models.<br />
<br />
<br />
===Jason McCullough (Iowa State)===<br />
<br />
Title: On the degrees and complexity of algebraic varieties<br />
<br />
Abstract: Given a system of polynomial equations in several variables, there are several natural questions regarding its associated solution set (algebraic variety): What is its dimension? Is it smooth or are there singularities? How is it embedded in affine/projective space? Free resolutions encode answers to all of these questions and are computable with modern computer algebra programs. This begs the question: can one bound the computational complexity of a variety in terms of readily available data? I will discuss two recently solved conjectures of Stillman and Eisenbud-Goto, how they relate to each other, and what they say about the complexity of algebraic varieties.<br />
<br />
===Maksym Radziwill (Caltech)===<br />
<br />
Title: Recent progress in multiplicative number theory<br />
<br />
Abstract: Multiplicative number theory aims to understand the ways in which integers factorize, and the distribution of integers with special multiplicative properties (such as primes). It is a central area of analytic number theory with various connections to L-functions, harmonic analysis, combinatorics, probability etc. At the core of the subject lie difficult questions such as the Riemann Hypothesis, and they set a benchmark for its accomplishments.<br />
An outstanding challenge in this field is to understand the multiplicative properties of integers linked by additive conditions, for instance n and n+ 1. A central conjecture making this precise is the Chowla-Elliott conjecture on correlations of multiplicative functions evaluated at consecutive integers. Until recently this conjecture appeared completely out of reach and was thought to be at least as difficult as showing the existence of infinitely many twin primes. These are also the kind of questions that lie beyond the capability of the Riemann Hypothesis. However recently the landscape of multiplicative number theory has been changing and we are no longer so certain about the limitations of our (new) tools. I will discuss the recent progress on these questions.<br />
<br />
===Jennifer Park (OSU)===<br />
<br />
Title: Rational points on varieties<br />
<br />
Abstract: The question of finding rational solutions to systems of polynomial equations has been investigated at least since the days of Pythagoras, but it is still not completely resolved (and in fact, it has been proven that there will never be an algorithm that answers this question!) Nonetheless, we will discuss various techniques that could answer this question in certain cases, and we will outline some conjectures related to this problem as well.<br />
<br />
===Ju-Lee Kim (MIT)===<br />
<br />
Title: Types and counting automorphic forms<br />
<br />
Abstract: We review the theory of types in representations of p-adic groups and discuss some applications for quantifying automorphic forms.<br />
<br />
===Eviatar Procaccia===<br />
<br />
Title: Can one hear the shape of a random walk?<br />
<br />
Abstract: We consider a Gibbs distribution over random walk paths on the square lattice, proportional to a random weight of the path’s boundary . We show that in the zero temperature limit, the paths condensate around an asymptotic shape. This limit shape is characterized as the minimizer of the functional, mapping open connected subsets of the plane to the sum of their principle eigenvalue and perimeter (with respect to the first passage percolation norm). A prime novel feature of this limit shape is that it is not in the class of Wulff shapes.<br />
Joint work with Marek Biskup (UCLA)<br />
<br />
===Jo Nelson (Rice)===<br />
<br />
Title: Contact Invariants and Reeb Dynamics<br />
<br />
Abstract: Contact geometry is the study of certain geometric structures on odd dimensional smooth manifolds. A contactstructure is a hyperplane field specified by a one form which satisfies a maximum nondegeneracy condition called complete non-integrability. The associated one form is called a contact form and uniquely determines a vector field called the Reeb vector field on the manifold. I will explain how to make use of J-holomorphic curves to obtain a Floer theoretic contact invariant, contact homology, whose chain complex is generated by closed Reeb orbits. In particular, I will explain the pitfalls in defining contact homology and discuss my work, in part joint with Hutchings, which provides rigorous constructions and applications to dynamics via geometric methods. This talk will feature numerous graphics to acclimate people to the realm of contact geometry. <br />
<br />
===Justin Hsu (Madison)===<br />
<br />
Title: From Couplings to Probabilistic Relational Program Logics<br />
<br />
Abstract: Many program properties are relational, comparing the behavior of a program (or even two different programs) on two different inputs. While researchers have developed various techniques for verifying such properties for standard, deterministic programs, relational properties for probabilistic programs have been more challenging. In this talk, I will survey recent developments targeting a range of probabilistic relational properties, with motivations from privacy, cryptography, and machine learning. The key idea is to meld relational program logics with an idea from probability theory, called probabilistic couplings. The logics allow a highly compositional and surprisingly general style of program analysis, supporting clean proofs for a broad array of probabilistic relational properties.<br />
<br />
=== Kavita Ramanan (Brown) ===<br />
Title: Tales of Random Projections<br />
<br />
Abstract: The interplay between geometry and probability in high-dimensional spaces is a subject of active research. Classical theorems in probability theory such as the central limit theorem and Cramer’s theorem can be viewed as providing information about certain scalar projections of high-dimensional product measures. In this talk we will describe the behavior of random projections of more general (possibly non-product) high-dimensional measures, which are of interest in diverse fields, ranging from asymptotic convex geometry to high-dimensional statistics. Although the study of (typical) projections of high-dimensional measures dates back to Borel, only recently has a theory begun to emerge, which in particular identifies the role of certain geometric assumptions that lead to better behaved projections. A particular question of interest is to identify what properties of the high-dimensional measure are captured by its lower-dimensional projections. While fluctuations of these projections have been studied over the past decade, we describe more recent work on the tail behavior of multidimensional projections, and associated conditional limit theorems.<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS19&diff=17107Applied/ACMS/absS192019-03-05T04:42:07Z<p>Craciun: </p>
<hr />
<div>= ACMS Abstracts: Spring 2019 =<br />
<br />
=== Jerry Zhu (University of Wisconsin-Madison, CS) ===<br />
''Machine Teaching: Optimal Control of Machine Learning''<br />
<br />
As machine learning is increasingly adopted in science and engineering, it becomes important to take a higher level view where the machine learner is only one of the agents in a multi-agent system. Other agents may have an incentive to control the learner. As examples, in adversarial machine learning an attacker can poison the training data to manipulate the model the learner learns; in education a teacher can optimize the curriculum to enhance student (modeled as a computational learning algorithm) performance. Machine teaching is optimal control theory applied to machine learning: the plant is the learner, the state is the learned model, and the control is the training data. In this talk I survey the mathematical foundation of machine teaching and the new research frontiers opened up by this confluence of machine learning and control theory.<br />
<br />
=== Abhishek Deshpande (UW-Madison, math) ===<br />
''Switches in chemical and biological networks''<br />
<br />
Switches are ubiquitous in both chemical and biological circuits. We explore the behaviour of autocatalytic switches in the context of the persistence conjecture. We show that networks without autocatalytic switches are persistent. The notion of a “critical siphon” forms the connecting link between autocatalysis and persistence. The talk will expand upon this connection.<br />
<br />
<br />
Swtiches are also relevant from a biological perspective. We show that catalytic switches help in reducing retroactivity - the back effect on the upstream system when connected to the downstream system. In addition, for certain catalytic networks like the push-pull motif, high rates of energy consumption are not required to attenuate retroactivity. One can accomplish this by reducing the coupling to the push-pull motif. However, this reduction in coupling is not robust to cross-talk caused by leak reactions.<br />
<br />
<br />
References:<br />
1) https://arxiv.org/abs/1309.3957<br />
2) https://arxiv.org/abs/1708.01792<br />
<br />
=== Chung-Nan Tzou (UW-Madison, Math)===<br />
''Fluid Models with Sharp Interfaces - Clouds and Plumes''<br />
<br />
In this talk, I will discuss two models describing the interaction of fluids across sharp interfaces. The first model is a discontinuous Poisson equation where the interfacial discontinuity arises from phase changes such as the interior and exterior of a cloud. A simple second-order numerical scheme aiming at solving this type of equations is proposed and tested. The second model is a simplified system of ODEs describing the mixing of jets and plumes with the ambient fluid. With the ambient density profile being sharply stratified, we established a criterion for a plume to be trapped underwater or rise to the top surface and also showed that this profile is the optimal mixer. This theory has been applied to the Gulf of Mexico oil spill incident and also compared with the data we collected through hands-on experiments in the fluids lab.<br />
<br />
=== Amy Cochran (UW-Madison, Math and Medical Informatics) ===<br />
''A model of online latent state learning''<br />
<br />
Researchers are increasingly interested in how humans perform a structured form of learning known as latent-state inferences. Latent state inferences refer to someone's ability to weigh competing hypotheses about one’s environment. Critically, this type of learning can help explain behavior and neural activity important to cognitive neuroscience and psychiatry. In this talk, I will first present a model of latent state learning that uses online, or recursive, updates. I will also discuss open questions related to this topic in hopes of generating discussion. Ultimately, I would like to engage students interested in the emerging area of computational psychiatry, as I will be joining the math department as an assistant professor in the Fall.<br />
<br />
=== Kui Ren (Columbia Applied math and UT-Austin Mathematics) ===<br />
''Uncertainty Characterization in Model-Based Inverse and Imaging Problems''<br />
<br />
In model-based inverse and imaging problems, it is often the case that only a portion of the relevant physical quantities in the model can be reconstructed/imaged. The rest of the model parameters are assumed to be known. In practice, these parameters are often only known partially (up to a certain accuracy). It is therefore important to characterize the dependence of the inversion/imaging results on the accuracy of these parameters. This is an uncertainty quantification problem that is challenging due to the fact that both the map from the uncertainty parameters (the ones we assumed partially known) to the measured data and the map from the measured data to the quantities to be imaged are difficult to analyze. In this talk, we review some recent computaitonal and mathematical results on such uncertainty characterization problems in nonlinear inverse problems for PDEs.<br />
<br />
=== Nicolas Garcia Trillos (UW-Madison, statistics) ===<br />
''Large sample asymptotics of spectra of Laplacians and semilinear elliptic PDEs on random geometric graphs''<br />
<br />
Given a data set $\mathcal{X}=\{x_1, \dots, x_n\}$ and a weighted graph structure $\Gamma= (\mathcal{X},W)$ on $\mathcal{X}$, graph based methods for learning use analytical notions like graph Laplacians, graph cuts, and Sobolev semi-norms to formulate optimization problems whose solutions serve as sensible approaches to machine learning tasks. When the data set consists of samples from a distribution supported on a manifold (or at least approximately so), and the weights depend inversely on the distance between the points, a natural question to study concerns the behavior of those optimization problems as the number of samples goes to infinity. In this talk I will focus on optimization problems closely connected to clustering and supervised regression that involve the graph Laplacian. For clustering, the spectrum of the graph Laplacian is the fundamental object used in the popular spectral clustering algorithm. For regression, the solution to a semilinear elliptic PDE on the graph provides the minimizer of an energy balancing regularization and data fidelity, a sensible object to use in non-parametric regression. <br />
Using tools from optimal transport, calculus of variations, and analysis of PDEs, I will discuss a series of results establishing the asymptotic consistency (with rates of convergence) of many of these analytical objects, as well as provide some perspectives on future research directions.<br />
<br />
=== Weiran Sun (Simon Fraser University) ===<br />
''Aggregation equations over bounded domains''<br />
<br />
Numerical computations have shown that due to the boundary effect, solutions of aggregation equations can evolve into non-energy minimizing states. Meanwhile, adding a small noise seems to bypass such non- energy minimizers. This motivates our study of aggregation equations over bounded domains. In this talk we will use basic probabilistic methods to show well-posedness and mean-field limits of aggregation equations with singular potentials (such as the Newtonian potential). We will also show the zero-diffusion limit of aggregations equations over bounded domains and obtain a convergence rate that is consistent with what has been observed in numerical simulations. This is joint work with Razvan Fetecau, Hui Huang, and Daniel Messenger.<br />
<br />
=== Jean-Luc Thiffeault (UW-Madison, Math) ===<br />
<br />
''The mathematics of burger flipping''<br />
<br />
Ever since the dawn of time people have (literally) asked the question<br />
&mdash; what is the most effective way to grill food? Timing is<br />
everything, since only one surface is exposed to heat at a given time.<br />
Should we flip only once, or many times? I will show a simple model<br />
of cooking by flipping, and some interesting mathematics will emerge.<br />
The rate of cooking depends on the spectrum of a linear operator, and<br />
on the fixed point of a map. If the system is symmetric, the rate of<br />
cooking becomes independent of the sequence of flips, as long as the<br />
last point to be cooked is the midpoint. This toy problem has some<br />
characteristics reminiscent of more realistic scenarios, such as<br />
thermal convection and heat exchangers.<br />
<br />
=== Alexandru Hening (Tufts University) ===<br />
<br />
''Stochastic persistence and extinction''<br />
<br />
A key question in population biology is understanding the conditions under which the species from an ecosystem persist or go extinct. Theoretical and empirical studies have shown that coexistence can be facilitated or negated by both biotic interactions and environmental fluctuations. We study the dynamics of n interacting species that live in a stochastic environment. Our models are described by n dimensional piecewise deterministic Markov processes. These are processes (X(t), r(t)) where the vector X denotes the density of the n species and r(t) is a finite state space process which keeps track of the environment. In any fixed environment the process follows the flow given by a system of ordinary differential equations. The randomness comes from the changes or switches in the environment, which happen at random times. We give sharp conditions under which the the populations persist as well as conditions under which some populations go extinct exponentially fast. As an example we look at the competitive exclusion principle from ecology and show how the random switching can `rescue' species from extinction. The talk is based on joint work with Dang H. Nguyen (University of Alabama).<br />
<br />
=== Lei Li (Shanghai Jiao Tong University) ===<br />
<br />
''The Random Batch Method and its application to sampling''<br />
<br />
First order interacting particle systems are ubiquitous. For example, they can be viewed as the over-damped Langevin equations. We first introduce a random algorithm, called the Random Batch Method (RBM), for simulating first order systems. The algorithms are motivated by the mini-batch idea in machine learning and statistics. Under some special conditions, we show the convergence of RBMs for the first marginal distribution under the Wasserstein distance. Compared with traditional tree code and fast multipole expansion algorithms, RBM works for kernels that do not necessarily decay. We then apply the RBM to Stein Variational Gradient Descent, a recent algorithm in statistics and machine learning, to obtain an efficient sampling method. This talk is based on joint work with Shi Jin (Shanghai Jiao Tong University), Jian-Guo Liu (Duke University), Jianfeng Lu (Duke University) and Zibu Liu (Duke University).</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=17106Applied/ACMS2019-03-05T04:34:52Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 25<br />
|[http://pages.cs.wisc.edu/~jerryzhu/ Jerry Zhu] (UW-Madison, CS)<br />
|''[[Applied/ACMS/absS19#Jerry Zhu (UW-Madison, CS)|Machine Teaching: Optimal Control of Machine Learning]]''<br />
| host<br />
|-<br />
| Feb 1<br />
|[https://www.math.wisc.edu/~deshpande/ Abhishek Deshpande] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Abhishek Deshpande (UW-Madison)|Switches in chemical and biological networks]]''<br />
| host<br />
|-<br />
| Feb 8<br />
|[https://www.math.wisc.edu/~cntzou/ Chung-Nan Tzou] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Chung-Nan Tzou (UW-Madison)|Fluid Models with Sharp Interfaces - Clouds and Plumes]]''<br />
| host<br />
|-<br />
| Feb 15<br />
|[https://sites.google.com/site/amylouisecochran/ Amy Cochran] (UW-Madison, Math and Medical Informatics)<br />
|''[[Applied/ACMS/absS19#Amy Cochran (UW-Madison, Math and Medical Informatics)|A model of online latent state learning]]''<br />
| host<br />
|-<br />
| Feb 22<br />
|[https://www.ma.utexas.edu/users/ren/index.html Kui Ren] (UT-Austin and Columbia)<br />
|''[[Applied/ACMS/absS19#Kui Ren (UT-Austin and Columbia)|Uncertainty Characterization in Model-Based Inverse and Imaging Problems]]''<br />
| host<br />
|-<br />
| Mar 1<br />
|[https://www.medphysics.wisc.edu/directory/guanghong.php Guanghong Chen] (UW-Madison, Medical Physics)<br />
|''[[Applied/ACMS/absS19#Guanghong Chen (UW-Madison, Medical Physics)|canceled]]''<br />
| Li<br />
|-<br />
| Mar 8<br />
|[http://www.nicolasgarciat.com/ Nicolas Garcia Trillos] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absS19#Nicolas Garcia Trillos (UW-Madison, Statistics)|Large sample asymptotics of spectra of Laplacians and semilinear elliptic PDEs on random geometric graphs]]''<br />
| host<br />
|-<br />
| Mar 15<br />
|[http://www.sfu.ca/~weirans/ Weiran Sun] (Simon Fraser)<br />
|''[[Applied/ACMS/absS19#Weiran Sun (Simon Fraser)|Aggregation equations over bounded domains]]''<br />
| host<br />
|-<br />
| Mar 22<br />
|[spring recess] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Mar 29<br />
|[http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault] (UW-Madison, Math)<br />
|''[[Applied/ACMS/absS19#Jean-Luc Thiffeault (UW-Madison, Math)|The mathematics of burger flipping]]''<br />
| self-hosted<br />
|-<br />
| Apr 5<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Apr 12<br />
|[https://sites.tufts.edu/hening/ Alexandru Hening] (Tufts University)<br />
|''[[Applied/ACMS/absS19#Alexandru Hening (Tufts University)|Stochastic persistence and extinction]]''<br />
| Craciun<br />
|-<br />
| Apr 19<br />
|[https://scholar.google.com/citations?user=85z4Cl4AAAAJ&hl=en Mustafa Mohamad] (NYU/Courant)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| Chen<br />
|-<br />
| Apr 26<br />
|[http://ins.sjtu.edu.cn/people/leili/ Lei Li] (Shanghai Jiao Tong University)<br />
|''[[Applied/ACMS/absS19#Lei Li (Shanghai Jiao Tong University)|The Random Batch Method and its application to sampling]]''<br />
| Spagnolie<br />
|-<br />
| May 3<br />
|[https://www.math.ucla.edu/~jiajun/ Jiajun Tong] (UCLA)<br />
|''[[Applied/ACMS/absS19#Jiajun Tong (UCLA)|title]]''<br />
| Chen<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2019&diff=16647Applied/ACMS/Spring20192019-01-18T01:24:35Z<p>Craciun: </p>
<hr />
<div>== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 25<br />
|[http://pages.cs.wisc.edu/~jerryzhu/ Jerry Zhu] (UW-Madison, CS)<br />
|''[[Applied/ACMS/absS19#Jerry Zhu (UW-Madison, CS)|title]]''<br />
| host<br />
|-<br />
| Feb 1<br />
|[https://www.math.wisc.edu/~cntzou/ Chung-Nan Tzou] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Chung-Nan Tzou (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 8<br />
|[https://www.math.wisc.edu/~deshpande/ Abhishek Deshpande] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Abhishek Deshpande (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 15<br />
|[https://sites.google.com/site/amylouisecochran/ Amy Cochran] (UW-Madison, Math and Medical Informatics)<br />
|''[[Applied/ACMS/absS19#Amy Cochran (UW-Madison, Math and Medical Informatics)|title]]''<br />
| host<br />
|-<br />
| Feb 22<br />
|[https://www.ma.utexas.edu/users/ren/index.html Kui Ren] (UT-Austin and Columbia)<br />
|''[[Applied/ACMS/absS19#Kui Ren (UT-Austin and Columbia)|title]]''<br />
| host<br />
|-<br />
| Mar 1<br />
|[https://www.medphysics.wisc.edu/directory/guanghong.php Guanghong Chen] (UW-Madison, Medical Physics)<br />
|''[[Applied/ACMS/absS19#Guanghong Chen (UW-Madison, Medical Physics)|title]]''<br />
| Li<br />
|-<br />
| Mar 8<br />
|[http://www.nicolasgarciat.com/ Nicolas Garcia Trillos] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absS19#Nicolas Garcia Trillos (UW-Madison, Statistics)|title]]''<br />
| host<br />
|-<br />
| Mar 15<br />
|[http://www.sfu.ca/~weirans/ Weiran Sun] (Simon Fraser)<br />
|''[[Applied/ACMS/absS19#Weiran Sun (Simon Fraser)|title]]''<br />
| host<br />
|-<br />
| Mar 22<br />
|[spring recess] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Mar 29<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (UC-Berkeley)<br />
|''[[Applied/ACMS/absS19#Lin Lin (UC-Berkeley)|title]]''<br />
| host<br />
|-<br />
| Apr 5<br />
|[https://scholar.google.com/citations?user=85z4Cl4AAAAJ&hl=en Mustafa Mohamad] (NYU/Courant)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| Chen<br />
|-<br />
| Apr 12<br />
|[https://sites.tufts.edu/hening/ Alexandru Hening] (Tufts University)<br />
|''[[Applied/ACMS/absS19#Alexandru Hening (Tufts University)|title TBA]]''<br />
| Craciun<br />
|-<br />
| Apr 19<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Apr 26<br />
|[http://ins.sjtu.edu.cn/people/leili/ Lei Li] (Shanghai Jiao Tong University)<br />
|''[[Applied/ACMS/absS19#Lei Li (Shanghai Jiao Tong University)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| May 3<br />
|[https://www.math.ucla.edu/~jiajun/ Jiajun Tong] (UCLA)<br />
|''[[Applied/ACMS/absS19#Jiajun Tong (UCLA)|title]]''<br />
| Chen<br />
|-</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2019&diff=16646Applied/ACMS/Spring20192019-01-18T01:23:02Z<p>Craciun: </p>
<hr />
<div>== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 25<br />
|[http://pages.cs.wisc.edu/~jerryzhu/ Jerry Zhu] (UW-Madison, CS)<br />
|''[[Applied/ACMS/absS19#Jerry Zhu (UW-Madison, CS)|title]]''<br />
| host<br />
|-<br />
| Feb 1<br />
|[https://www.math.wisc.edu/~cntzou/ Chung-Nan Tzou] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Chung-Nan Tzou (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 8<br />
|[https://www.math.wisc.edu/~deshpande/ Abhishek Deshpande] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Abhishek Deshpande (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 15<br />
|[https://sites.google.com/site/amylouisecochran/ Amy Cochran] (UW-Madison, Math and Medical Informatics)<br />
|''[[Applied/ACMS/absS19#Amy Cochran (UW-Madison, Math and Medical Informatics)|title]]''<br />
| host<br />
|-<br />
| Feb 22<br />
|[https://www.ma.utexas.edu/users/ren/index.html Kui Ren] (UT-Austin and Columbia)<br />
|''[[Applied/ACMS/absS19#Kui Ren (UT-Austin and Columbia)|title]]''<br />
| host<br />
|-<br />
| Mar 1<br />
|[https://www.medphysics.wisc.edu/directory/guanghong.php Guanghong Chen] (UW-Madison, Medical Physics)<br />
|''[[Applied/ACMS/absS19#Guanghong Chen (UW-Madison, Medical Physics)|title]]''<br />
| Li<br />
|-<br />
| Mar 8<br />
|[http://www.nicolasgarciat.com/ Nicolas Garcia Trillos] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absS19#Nicolas Garcia Trillos (UW-Madison, Statistics)|title]]''<br />
| host<br />
|-<br />
| Mar 15<br />
|[http://www.sfu.ca/~weirans/ Weiran Sun] (Simon Fraser)<br />
|''[[Applied/ACMS/absS19#Weiran Sun (Simon Fraser)|title]]''<br />
| host<br />
|-<br />
| Mar 22<br />
|[spring recess] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Mar 29<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (UC-Berkeley)<br />
|''[[Applied/ACMS/absS19#Lin Lin (UC-Berkeley)|title]]''<br />
| host<br />
|-<br />
| Apr 5<br />
|[https://scholar.google.com/citations?user=85z4Cl4AAAAJ&hl=en Mustafa Mohamad] (NYU/Courant)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| Chen<br />
|-<br />
| Apr 12<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Alexandru Hening (Tufts University)|title TBA]]''<br />
| Craciun<br />
|-<br />
| Apr 19<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Apr 26<br />
|[http://ins.sjtu.edu.cn/people/leili/ Lei Li] (Shanghai Jiao Tong University)<br />
|''[[Applied/ACMS/absS19#Lei Li (Shanghai Jiao Tong University)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| May 3<br />
|[https://www.math.ucla.edu/~jiajun/ Jiajun Tong] (UCLA)<br />
|''[[Applied/ACMS/absS19#Jiajun Tong (UCLA)|title]]''<br />
| Chen<br />
|-</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2019&diff=16645Applied/ACMS/Spring20192019-01-18T01:21:24Z<p>Craciun: </p>
<hr />
<div>== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 25<br />
|[http://pages.cs.wisc.edu/~jerryzhu/ Jerry Zhu] (UW-Madison, CS)<br />
|''[[Applied/ACMS/absS19#Jerry Zhu (UW-Madison, CS)|title]]''<br />
| host<br />
|-<br />
| Feb 1<br />
|[https://www.math.wisc.edu/~cntzou/ Chung-Nan Tzou] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Chung-Nan Tzou (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 8<br />
|[https://www.math.wisc.edu/~deshpande/ Abhishek Deshpande] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Abhishek Deshpande (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 15<br />
|[https://sites.google.com/site/amylouisecochran/ Amy Cochran] (UW-Madison, Math and Medical Informatics)<br />
|''[[Applied/ACMS/absS19#Amy Cochran (UW-Madison, Math and Medical Informatics)|title]]''<br />
| host<br />
|-<br />
| Feb 22<br />
|[https://www.ma.utexas.edu/users/ren/index.html Kui Ren] (UT-Austin and Columbia)<br />
|''[[Applied/ACMS/absS19#Kui Ren (UT-Austin and Columbia)|title]]''<br />
| host<br />
|-<br />
| Mar 1<br />
|[https://www.medphysics.wisc.edu/directory/guanghong.php Guanghong Chen] (UW-Madison, Medical Physics)<br />
|''[[Applied/ACMS/absS19#Guanghong Chen (UW-Madison, Medical Physics)|title]]''<br />
| Li<br />
|-<br />
| Mar 8<br />
|[http://www.nicolasgarciat.com/ Nicolas Garcia Trillos] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absS19#Nicolas Garcia Trillos (UW-Madison, Statistics)|title]]''<br />
| host<br />
|-<br />
| Mar 15<br />
|[http://www.sfu.ca/~weirans/ Weiran Sun] (Simon Fraser)<br />
|''[[Applied/ACMS/absS19#Weiran Sun (Simon Fraser)|title]]''<br />
| host<br />
|-<br />
| Mar 22<br />
|[spring recess] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Mar 29<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (UC-Berkeley)<br />
|''[[Applied/ACMS/absS19#Lin Lin (UC-Berkeley)|title]]''<br />
| host<br />
|-<br />
| Apr 5<br />
|[https://scholar.google.com/citations?user=85z4Cl4AAAAJ&hl=en Mustafa Mohamad] (NYU/Courant)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| Chen<br />
|-<br />
| Apr 12<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Alexandru Hening (Institute)|title]]''<br />
| Craciun<br />
|-<br />
| Apr 19<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Tufts University)|title TBA]]''<br />
| host<br />
|-<br />
| Apr 26<br />
|[http://ins.sjtu.edu.cn/people/leili/ Lei Li] (Shanghai Jiao Tong University)<br />
|''[[Applied/ACMS/absS19#Lei Li (Shanghai Jiao Tong University)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| May 3<br />
|[https://www.math.ucla.edu/~jiajun/ Jiajun Tong] (UCLA)<br />
|''[[Applied/ACMS/absS19#Jiajun Tong (UCLA)|title]]''<br />
| Chen<br />
|-</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2019&diff=16644Applied/ACMS/Spring20192019-01-18T01:16:50Z<p>Craciun: </p>
<hr />
<div>== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 25<br />
|[http://pages.cs.wisc.edu/~jerryzhu/ Jerry Zhu] (UW-Madison, CS)<br />
|''[[Applied/ACMS/absS19#Jerry Zhu (UW-Madison, CS)|title]]''<br />
| host<br />
|-<br />
| Feb 1<br />
|[https://www.math.wisc.edu/~cntzou/ Chung-Nan Tzou] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Chung-Nan Tzou (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 8<br />
|[https://www.math.wisc.edu/~deshpande/ Abhishek Deshpande] (UW-Madison)<br />
|''[[Applied/ACMS/absS19#Abhishek Deshpande (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 15<br />
|[https://sites.google.com/site/amylouisecochran/ Amy Cochran] (UW-Madison, Math and Medical Informatics)<br />
|''[[Applied/ACMS/absS19#Amy Cochran (UW-Madison, Math and Medical Informatics)|title]]''<br />
| host<br />
|-<br />
| Feb 22<br />
|[https://www.ma.utexas.edu/users/ren/index.html Kui Ren] (UT-Austin and Columbia)<br />
|''[[Applied/ACMS/absS19#Kui Ren (UT-Austin and Columbia)|title]]''<br />
| host<br />
|-<br />
| Mar 1<br />
|[https://www.medphysics.wisc.edu/directory/guanghong.php Guanghong Chen] (UW-Madison, Medical Physics)<br />
|''[[Applied/ACMS/absS19#Guanghong Chen (UW-Madison, Medical Physics)|title]]''<br />
| Li<br />
|-<br />
| Mar 8<br />
|[http://www.nicolasgarciat.com/ Nicolas Garcia Trillos] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absS19#Nicolas Garcia Trillos (UW-Madison, Statistics)|title]]''<br />
| host<br />
|-<br />
| Mar 15<br />
|[http://www.sfu.ca/~weirans/ Weiran Sun] (Simon Fraser)<br />
|''[[Applied/ACMS/absS19#Weiran Sun (Simon Fraser)|title]]''<br />
| host<br />
|-<br />
| Mar 22<br />
|[spring recess] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Mar 29<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (UC-Berkeley)<br />
|''[[Applied/ACMS/absS19#Lin Lin (UC-Berkeley)|title]]''<br />
| host<br />
|-<br />
| Apr 5<br />
|[https://scholar.google.com/citations?user=85z4Cl4AAAAJ&hl=en Mustafa Mohamad] (NYU/Courant)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| Chen<br />
|-<br />
| Apr 12<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Apr 19<br />
|[website TBA] (Institute)<br />
|''[[Applied/ACMS/absS19#Name (Institute)|title]]''<br />
| host<br />
|-<br />
| Apr 26<br />
|[http://ins.sjtu.edu.cn/people/leili/ Lei Li] (Shanghai Jiao Tong University)<br />
|''[[Applied/ACMS/absS19#Lei Li (Shanghai Jiao Tong University)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| May 3<br />
|[https://www.math.ucla.edu/~jiajun/ Jiajun Tong] (UCLA)<br />
|''[[Applied/ACMS/absS19#Jiajun Tong (UCLA)|title]]''<br />
| Chen<br />
|-</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=16514Applied/ACMS2018-12-01T15:55:06Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept. 14<br />
|[http://www.northeastern.edu/tzhou/ Ting Zhou] (Northeastern)<br />
|''[[Applied/ACMS/absF18#Ting Zhou (Northeastern Univ.)|Nonparaxial near-nondiffracting accelerating optical beams]]''<br />
|Li<br />
|-<br />
| Sept. 21<br />
|[https://sites.google.com/a/brown.edu/sanz-alonso/ Daniel Sanz-Alonso] (Chicago)<br />
|''[[Applied/ACMS/absF18#Daniel Sanz-Alonso (Chicago Univ.)|Discrete and Continuous Learning in Information and Geophysical Sciences]]''<br />
|Chen<br />
|-<br />
| Sept. 28<br />
|[https://www.math.wisc.edu/~chennan/ Nan Chen] (UW-Madison)<br />
|''[[Applied/ACMS/absF18#Chen (UW-Madison)|A simple stochastic model for El Nino with westerly wind bursts and the prediction of super El Nino events]]''<br />
|Li<br />
|-<br />
| Oct. 5<br />
|[https://sites.google.com/site/sulianthual/ Sulian Thual] (Fudan University)<br />
|''[[Applied/ACMS/absF18#Thual (Fudan)|A Stochastic Skeleton Model for the Madden-Julian Oscillation and El Nino-Southern Oscillation]]''<br />
|Chen, Stechmann<br />
|-<br />
| Oct. 12<br />
|[http://www.damtp.cam.ac.uk/people/mt748/ Matthew Thorpe] (Cambridge University)<br />
|''[[Applied/ACMS/absF18#Thorpe (Cambridge)|Continuum Limits of Semi-Supervised Learning on Graphs]]''<br />
|Chen<br />
|-<br />
| Oct. 19<br />
|[http://www.math.jhu.edu/~feilu/ Fei Lu] (Johns Hopkins)<br />
|''[[Applied/ACMS/absF18#Lu (JHU)|Data-informed stochastic model reduction for complex dynamical systems]]''<br />
|Chen<br />
|-<br />
| Oct. 26<br />
|[https://stuart.iit.edu/faculty/matthew-dixon Matthew Dixon] (Illinois Institute of Technoology)<br />
|''[[Applied/ACMS/absF18#Matthew Dixon (Illinois Institute of Technology)|"Quantum Equilibrium-Disequilibrium”: Asset Price Dynamics, Symmetry Breaking and Defaults as Dissipative Instantons<br />
]]''<br />
|Jean-Luc<br />
|-<br />
| Nov. 2<br />
|[http://www.stat.wisc.edu/~karlrohe/homepage/Welcome.html Karl Rohe] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absF18#Karl Rohe (UW-Madison)|Making Spectral Graph Theory work in practice. Making the practice work in theory]]''<br />
|host<br />
|-<br />
| Nov. 9<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI)<br />
|''[[Applied/ACMS/absF18#Yimin Zhong (UCI)|Instability of an inverse problem for the stationary radiative transport near the diffusion limit]]''<br />
|Li<br />
|-<br />
| Nov. 16<br />
|[http://www.math.wisc.edu/~alfredowetzel/ Alfredo N Wetzel] (UW-Madison)<br />
|''[[Applied/ACMS/absF18#Alfredo Wetzel (UW-Madison)|Discontinuous Fronts as Exact Solutions to Precipitating Quasi-Geostrophy]]''<br />
|Local<br />
|-<br />
| Dec. 14<br />
|[http://www.einkemmer.net/ Lukas Einkemmer] (University of Tübingen and University of Innsbruck)<br />
|''[[Applied/ACMS/absF18#Lukas Einkemmer (University of Innsbruck)| TBA<br />
]]''<br />
|Li<br />
|-<br />
| <br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=16512Applied/ACMS2018-12-01T05:36:52Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept. 14<br />
|[http://www.northeastern.edu/tzhou/ Ting Zhou] (Northeastern)<br />
|''[[Applied/ACMS/absF18#Ting Zhou (Northeastern Univ.)|Nonparaxial near-nondiffracting accelerating optical beams]]''<br />
|Li<br />
|-<br />
| Sept. 21<br />
|[https://sites.google.com/a/brown.edu/sanz-alonso/ Daniel Sanz-Alonso] (Chicago)<br />
|''[[Applied/ACMS/absF18#Daniel Sanz-Alonso (Chicago Univ.)|Discrete and Continuous Learning in Information and Geophysical Sciences]]''<br />
|Chen<br />
|-<br />
| Sept. 28<br />
|[https://www.math.wisc.edu/~chennan/ Nan Chen] (UW-Madison)<br />
|''[[Applied/ACMS/absF18#Chen (UW-Madison)|A simple stochastic model for El Nino with westerly wind bursts and the prediction of super El Nino events]]''<br />
|Li<br />
|-<br />
| Oct. 5<br />
|[https://sites.google.com/site/sulianthual/ Sulian Thual] (Fudan University)<br />
|''[[Applied/ACMS/absF18#Thual (Fudan)|A Stochastic Skeleton Model for the Madden-Julian Oscillation and El Nino-Southern Oscillation]]''<br />
|Chen, Stechmann<br />
|-<br />
| Oct. 12<br />
|[http://www.damtp.cam.ac.uk/people/mt748/ Matthew Thorpe] (Cambridge University)<br />
|''[[Applied/ACMS/absF18#Thorpe (Cambridge)|Continuum Limits of Semi-Supervised Learning on Graphs]]''<br />
|Chen<br />
|-<br />
| Oct. 19<br />
|[http://www.math.jhu.edu/~feilu/ Fei Lu] (Johns Hopkins)<br />
|''[[Applied/ACMS/absF18#Lu (JHU)|Data-informed stochastic model reduction for complex dynamical systems]]''<br />
|Chen<br />
|-<br />
| Oct. 26<br />
|[https://stuart.iit.edu/faculty/matthew-dixon Matthew Dixon] (Illinois Institute of Technoology)<br />
|''[[Applied/ACMS/absF18#Matthew Dixon (Illinois Institute of Technology)|"Quantum Equilibrium-Disequilibrium”: Asset Price Dynamics, Symmetry Breaking and Defaults as Dissipative Instantons<br />
]]''<br />
|Jean-Luc<br />
|-<br />
| Nov. 2<br />
|[http://www.stat.wisc.edu/~karlrohe/homepage/Welcome.html Karl Rohe] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absF18#Karl Rohe (UW-Madison)|Making Spectral Graph Theory work in practice. Making the practice work in theory]]''<br />
|host<br />
|-<br />
| Nov. 9<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI)<br />
|''[[Applied/ACMS/absF18#Yimin Zhong (UCI)|Instability of an inverse problem for the stationary radiative transport near the diffusion limit]]''<br />
|Li<br />
|-<br />
| Nov. 16<br />
|[http://www.math.wisc.edu/~alfredowetzel/ Alfredo N Wetzel] (UW-Madison)<br />
|''[[Applied/ACMS/absF18#Alfredo Wetzel (UW-Madison)|Discontinuous Fronts as Exact Solutions to Precipitating Quasi-Geostrophy]]''<br />
|Local<br />
|-<br />
| Dec. 7<br />
|[TBA] (TBA)<br />
|''[[TBA| TBA<br />
]]''<br />
|Ifrim and Craciun<br />
|-<br />
| Dec. 14<br />
|[http://www.einkemmer.net/ Lukas Einkemmer] (University of Tübingen and University of Innsbruck)<br />
|''[[Applied/ACMS/absF18#Lukas Einkemmer (University of Innsbruck)| TBA<br />
]]''<br />
|Li<br />
|-<br />
| <br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=16511Applied/ACMS2018-12-01T05:35:43Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept. 14<br />
|[http://www.northeastern.edu/tzhou/ Ting Zhou] (Northeastern)<br />
|''[[Applied/ACMS/absF18#Ting Zhou (Northeastern Univ.)|Nonparaxial near-nondiffracting accelerating optical beams]]''<br />
|Li<br />
|-<br />
| Sept. 21<br />
|[https://sites.google.com/a/brown.edu/sanz-alonso/ Daniel Sanz-Alonso] (Chicago)<br />
|''[[Applied/ACMS/absF18#Daniel Sanz-Alonso (Chicago Univ.)|Discrete and Continuous Learning in Information and Geophysical Sciences]]''<br />
|Chen<br />
|-<br />
| Sept. 28<br />
|[https://www.math.wisc.edu/~chennan/ Nan Chen] (UW-Madison)<br />
|''[[Applied/ACMS/absF18#Chen (UW-Madison)|A simple stochastic model for El Nino with westerly wind bursts and the prediction of super El Nino events]]''<br />
|Li<br />
|-<br />
| Oct. 5<br />
|[https://sites.google.com/site/sulianthual/ Sulian Thual] (Fudan University)<br />
|''[[Applied/ACMS/absF18#Thual (Fudan)|A Stochastic Skeleton Model for the Madden-Julian Oscillation and El Nino-Southern Oscillation]]''<br />
|Chen, Stechmann<br />
|-<br />
| Oct. 12<br />
|[http://www.damtp.cam.ac.uk/people/mt748/ Matthew Thorpe] (Cambridge University)<br />
|''[[Applied/ACMS/absF18#Thorpe (Cambridge)|Continuum Limits of Semi-Supervised Learning on Graphs]]''<br />
|Chen<br />
|-<br />
| Oct. 19<br />
|[http://www.math.jhu.edu/~feilu/ Fei Lu] (Johns Hopkins)<br />
|''[[Applied/ACMS/absF18#Lu (JHU)|Data-informed stochastic model reduction for complex dynamical systems]]''<br />
|Chen<br />
|-<br />
| Oct. 26<br />
|[https://stuart.iit.edu/faculty/matthew-dixon Matthew Dixon] (Illinois Institute of Technoology)<br />
|''[[Applied/ACMS/absF18#Matthew Dixon (Illinois Institute of Technology)|"Quantum Equilibrium-Disequilibrium”: Asset Price Dynamics, Symmetry Breaking and Defaults as Dissipative Instantons<br />
]]''<br />
|Jean-Luc<br />
|-<br />
| Nov. 2<br />
|[http://www.stat.wisc.edu/~karlrohe/homepage/Welcome.html Karl Rohe] (UW-Madison, Statistics)<br />
|''[[Applied/ACMS/absF18#Karl Rohe (UW-Madison)|Making Spectral Graph Theory work in practice. Making the practice work in theory]]''<br />
|host<br />
|-<br />
| Nov. 9<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI)<br />
|''[[Applied/ACMS/absF18#Yimin Zhong (UCI)|Instability of an inverse problem for the stationary radiative transport near the diffusion limit]]''<br />
|Li<br />
|-<br />
| Nov. 16<br />
|[http://www.math.wisc.edu/~alfredowetzel/ Alfredo N Wetzel] (UW-Madison)<br />
|''[[Applied/ACMS/absF18#Alfredo Wetzel (UW-Madison)|Discontinuous Fronts as Exact Solutions to Precipitating Quasi-Geostrophy]]''<br />
|Local<br />
|-<br />
| Dec. 7<br />
|[TBA] (TBA)<br />
|''[[TBA| TBA<br />
]]''<br />
|Craciun<br />
|-<br />
| Dec. 14<br />
|[http://www.einkemmer.net/ Lukas Einkemmer] (University of Tübingen and University of Innsbruck)<br />
|''[[Applied/ACMS/absF18#Lukas Einkemmer (University of Innsbruck)| TBA<br />
]]''<br />
|Li<br />
|-<br />
| <br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=File:Putnam_Oct_3_2018.pdf&diff=16314File:Putnam Oct 3 2018.pdf2018-10-30T04:31:47Z<p>Craciun: </p>
<hr />
<div></div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16313Putnam Club2018-10-30T04:31:25Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We also hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
'''! Important announcement:''' We put together a Piazza account that will help the participants to discuss and collaborate with their pairs. Here is the link you need to access in order to register for this "class": piazza.com/wisc/fall2018/putnam2018 . Our intervention on Piazza will be minimal (some of the instructors will, from time to time, visit the piazza questions and provide some help). Also, based on your requests, we have decided to structure our meetings in a way that will provide more insight on methods and certain tricks that are very often used in this type of math competitions. The book we will mainly use as a guide in preparing our meetings is: "Putnam and Beyond" by Razvan Gelca and Titu Andreescu. <br />
<br />
<br />
<br />
* September 26: topic [[Media:Putnam_26_sept_2018.pdf | Introductory meeting]] by Mihaela Ifrim. We covered only the first 3 problems. I encourage you to work out all the problems!<br />
<br />
* October 3: [[Media:Putnam_Oct_3_2018.pdf | Linear Algebra]] by George Craciun.<br />
<br />
* October 10: [[Media:Putnam polynomials 2018.pdf | Polynomials]] by Botong Wang.<br />
<br />
* October 17: [[Media:SeqPut18.pdf | Sequences]] by Alex Hanhart.<br />
<br />
* October 24: [[Media:Putnam_Oct_24th_2018.pdf | Convergence and Continuity]] by Mihaela Ifrim.<br />
<br />
* October 27: Virginia Tech Math Contest: 9-11:30am in VV B115.<br />
<br />
* October 31: [[Media:Putnam_Oct_31_2018.pdf | Geometry: cartesian coordinates, complex coordinates, circles and conics]] by George Craciun.<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=File:Putnam_Oct_31_2018.pdf&diff=16312File:Putnam Oct 31 2018.pdf2018-10-30T03:57:22Z<p>Craciun: </p>
<hr />
<div></div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16311Putnam Club2018-10-30T03:56:40Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We also hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
'''! Important announcement:''' We put together a Piazza account that will help the participants to discuss and collaborate with their pairs. Here is the link you need to access in order to register for this "class": piazza.com/wisc/fall2018/putnam2018 . Our intervention on Piazza will be minimal (some of the instructors will, from time to time, visit the piazza questions and provide some help). Also, based on your requests, we have decided to structure our meetings in a way that will provide more insight on methods and certain tricks that are very often used in this type of math competitions. The book we will mainly use as a guide in preparing our meetings is: "Putnam and Beyond" by Razvan Gelca and Titu Andreescu. <br />
<br />
<br />
<br />
* September 26: topic [[Media:Putnam_26_sept_2018.pdf | Introductory meeting]] by Mihaela Ifrim. We covered only the first 3 problems. I encourage you to work out all the problems!<br />
<br />
* October 3: Linear Algebra by George Craciun.<br />
<br />
* October 10: [[Media:Putnam polynomials 2018.pdf | Polynomials]] by Botong Wang.<br />
<br />
* October 17: [[Media:SeqPut18.pdf | Sequences]] by Alex Hanhart.<br />
<br />
* October 24: [[Media:Putnam_Oct_24th_2018.pdf | Convergence and Continuity]] by Mihaela Ifrim.<br />
<br />
* October 27: Virginia Tech Math Contest: 9-11:30am in VV B115.<br />
<br />
* October 31: [[Media:Putnam_Oct_31_2018.pdf | Geometry: cartesian coordinates, complex coordinates, circles and conics]] by George Craciun.<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16310Putnam Club2018-10-30T03:28:33Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We also hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
'''! Important announcement:''' We put together a Piazza account that will help the participants to discuss and collaborate with their pairs. Here is the link you need to access in order to register for this "class": piazza.com/wisc/fall2018/putnam2018 . Our intervention on Piazza will be minimal (some of the instructors will, from time to time, visit the piazza questions and provide some help). Also, based on your requests, we have decided to structure our meetings in a way that will provide more insight on methods and certain tricks that are very often used in this type of math competitions. The book we will mainly use as a guide in preparing our meetings is: "Putnam and Beyond" by Razvan Gelca and Titu Andreescu. <br />
<br />
<br />
<br />
* September 26: topic [[Media:Putnam_26_sept_2018.pdf | Introductory meeting]] by Mihaela Ifrim. We covered only the first 3 problems. I encourage you to work out all the problems!<br />
<br />
* October 3: Linear Algebra by George Craciun.<br />
<br />
* October 10: [[Media:Putnam polynomials 2018.pdf | Polynomials]] by Botong Wang.<br />
<br />
* October 17: [[Media:SeqPut18.pdf | Sequences]] by Alex Hanhart.<br />
<br />
* October 24: [[Media:Putnam_Oct_24th_2018.pdf | Convergence and Continuity]] by Mihaela Ifrim.<br />
<br />
* October 27: Virginia Tech Math Contest: 9-11:30am in VV B115.<br />
<br />
* October 31: Geometry: circles and other conics, by George Craciun.<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16308Putnam Club2018-10-30T03:15:21Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We also hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
'''! Important announcement:''' We put together a Piazza account that will help the participants to discuss and collaborate with their pairs. Here is the link you need to access in order to register for this "class": piazza.com/wisc/fall2018/putnam2018 . Our intervention on Piazza will be minimal (some of the instructors will, from time to time, visit the piazza questions and provide some help). Also, based on your requests, we have decided to structure our meetings in a way that will provide more insight on methods and certain tricks that are very often used in this type of math competitions. The book we will mainly use as a guide in preparing our meetings is: "Putnam and Beyond" by Razvan Gelca and Titu Andreescu. <br />
<br />
<br />
<br />
* September 26: topic [[Media:Putnam_26_sept_2018.pdf | Introductory meeting]] by Mihaela Ifrim. We covered only the first 3 problems. I encourage you to work out all the problems!<br />
<br />
* October 3: Linear Algebra by George Craciun.<br />
<br />
* October 10: [[Media:Putnam polynomials 2018.pdf | Polynomials]] by Botong Wang.<br />
<br />
* October 17: [[Media:SeqPut18.pdf | Sequences]] by Alex Hanhart.<br />
<br />
* October 24: [[Media:Putnam_Oct_24th_2018.pdf | Convergence and Continuity]] by Mihaela Ifrim.<br />
<br />
* October 27: Virginia Tech Math Contest: 9-11:30am in VV B115.<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16058Putnam Club2018-09-24T16:31:28Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We also hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
* September 26: topic TBA<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16057Putnam Club2018-09-24T16:30:22Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
* September 26: topic TBA<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16056Putnam Club2018-09-24T16:30:06Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: , Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
* September 26: topic TBA<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16055Putnam Club2018-09-24T16:29:22Z<p>Craciun: Undo revision 16054 by Craciun (talk)</p>
<hr />
<div><br />
''Organizers: , Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
* September TBA<br />
<br />
==Spring 2018==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16054Putnam Club2018-09-24T16:27:49Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: , Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
* September TBA<br />
<br />
==Spring 2017==<br />
<br />
The Putnam Club does not meet in the spring, but we will have the fifth annual UW [[Undergraduate Math Competition]] in '''April 2019'''.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16053Putnam Club2018-09-24T15:53:11Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: , Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We hold our own UW Madison [[Undergraduate Math Competition]] in the spring; for this academic year, it is tentatively scheduled in April 2019.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. '''The first meeting will be on the 26th of September in Van Vleck hall, room B139.'''<br />
<br />
* September TBA<br />
<br />
==Spring 2017==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Putnam_Club&diff=16052Putnam Club2018-09-24T15:51:03Z<p>Craciun: </p>
<hr />
<div><br />
''Organizers: , Gheorghe Craciun, Alexander Hanhart, Mihaela Ifrim, Botong Wang''<br />
<br />
The Putnam Exam, offered by the Mathematical Association of America, is the premier American math competition for undergraduate students. It is given each year on the first Saturday in December. The exam consists of 12 problems, 6 in the 3 hour morning session and 6 in the 3 hour afternoon session. Each problem is worth 10 points, so the maximum score is 120. National winners usually get around 100 points. The median score is generally around 0-2 points. This is a difficult exam with many interesting and fun problems.<br />
<br />
[http://kskedlaya.org/putnam-archive/ Old exams and more information on the Putnam competition.]<br />
<br />
The UW is also participating in the Virginia Tech Regional Mathematics Contest. This is an individual competition with seven problems in 2.5 hours. Many schools use it as a kind of rehearsal for the Putnam. You can find more information [http://www.math.vt.edu/people/plinnell/Vtregional/ over here.]<br />
<br />
We hold our own UW Madison [[Undergraduate Math Competition]] in the spring; this year, it is on '''April 24th, 2018'''.<br />
<br />
==Fall 2018==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139. The first meeting will be on the 26th of September in Van Vleck hall, room B139.<br />
<br />
* September TBA<br />
<br />
==Spring 2017==<br />
<br />
The Putnam Club does not meet in the spring, but we had the fourth annual UW [[Undergraduate Math Competition]] on '''April 24th''', 2018, 5:30-8pm in VV B239.<br />
<br />
==Fall 2017==<br />
<br />
The Putnam Club will help you prepare for the exam by practicing on problems from previous years and other olympiad-style problems. The meeting time is 5pm on Wednesdays in VV B139.<br />
<br />
* September 20: [[Media:Putnam092017.pdf | Introductory meeting]] by D.Arinkin<br />
* September 27: [[Media:Putnam092717.pdf | Equations with functions as unknowns]] by M.Ifrim (by request: here is [[Media:Putnam092717sol6.pdf | a solution to problem 6]]; problem 7 is problem B5 of 2016 Putnam exam; you can see the solution [http://kskedlaya.org/putnam-archive/2016s.pdf here]).<br />
* October 4: [[Media:Putnam100417.pdf | Inequalities ]] by G.Craciun.<br />
* October 11: [[Media:Putnam101117.pdf | Polynomials ]] by D.Arinkin.<br />
* October 18: [[Media:Putnam1(2)..pdf | Equations ]] by M. Ifrim<br />
* October 21: Virginia Tech Math Contest: 9-11:30am in VV B203.<br />
* October 25: Review of this year's [[Media:VTRMC2017.pdf | Virginia Tech Contest]] by G.Craciun.<br />
* November 1: [[Media:Putnam110117.pdf | Functions and calculus]] by D.Arinkin.<br />
* November 8: [[Media:Putnam1.pdf | Past Competitions]] by M.Ifrim<br />
* November 15: [[Media:Putnam111517.pdf | Recurrences]] by G.Craciun.<br />
* November 22: '''No meeting''': Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112917.pdf | Complex numbers]] by D.Arinkin.<br />
* December 2: '''Putnam Exam''' in VVB115. Morning session: 9-12pm; Afternoon session: 2-5pm.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the third annual UW [[Undergraduate Math Competition]] on April 19th, 2017.<br />
<br />
==Fall 2016==<br />
<br />
* September 20: [[Media:Putnam092016.pdf | Introductory meeting]]<br />
* September 27: [[Media:Putnam092716.pdf | Calculus and analysis]]<br />
* October 4: [[Media:Putnam100416.pdf | Generating functions]] (by Vlad Matei) <br />
* October 11: [[Media:UWUMC2016.pdf | Review of last year's UW Math competition]]<br />
* October 18: [[Media:Putnam101816.pdf | Functional equations]]<br />
* October 22: Virginia Tech Math Contest<br />
* October 25: Review of this year's [[Media:vtrmc16.pdf | VT contest]]<br />
* November 1: [[Media:Putnam110116.pdf | Matrices]] (by Vlad Matei)<br />
* November 15: [[Media:Putnam111516.pdf | Two algebra problems]]<br />
* November 22: No meeting: Happy Thanksgiving!<br />
* November 29: [[Media:Putnam112916.pdf | Assorted problems]]<br />
* December 3: Putnam Exam: Morning session: 9am-noon, Afternoon session: 2-5pm in VV B135.<br />
<br />
==Spring 2016==<br />
<br />
The Putnam Club does not meet in the spring, but we had the second annual UW [[Undergraduate Math Competition]] on April 12th, 2016.<br />
<br />
==Fall 2015==<br />
. <br />
* September 23rd: [[Media:Putnam092315.pdf | Introductory meeting]]<br />
* September 30th: [[Media:Putnam093015.pdf | Pigeonhole principle]]<br />
* October 7th: Review of [[Media:UWUMC2015.pdf | 2015 UW math competition]]<br />
* October 14th: [[Media:Putnam101415.pdf | Matrices and determinants]]<br />
* October 21st: [[Media:Putnam102115.pdf | Virginia Tech practice]]<br />
* October 24th: Virginia Tech Regional Mathematics Contest: 9-11:30 am<br />
* October 28th: Review of the 2015 Virginia Tech contest.<br />
* November 4th: [[Media:PutnamProblemsOct12.pdf | Polynomials]]<br />
* November 11th: [[Media:PutnamProblemsNov11.pdf | Assorted problems]]<br />
* November 18th: [[Media:PutnamProblemsNov18.pdf | Assorted problems]]<br />
* No meeting on November 25th<br />
* December 2nd: TBA<br />
* December 5th: Putnam competition: Morning session: 9am-12pm, afternoon session: 2-5pm in VV B115.<br />
<br />
==Spring 2015==<br />
<br />
The Putnam Club does not meet in the spring, but we had our first UW [[Undergraduate Math Competition]]!<br />
<br />
==Fall 2014==<br />
<br />
* September 17: [[Media:Putnam091714.pdf | Introductory meeting]]<br />
* September 22: [[Media:Putnam092214.pdf | Coloring and pigeonhole principle]]<br />
* October 1st: Went through HW problems from last time<br />
* October 8th: [[Media:Putnam100814.pdf | Number theory]]<br />
* October 15th: [[Media:Putnam101514.pdf | Games]]<br />
* October 22nd: [[Media:VTRMC13.pdf | Problems from last year's Virginia Tech contest]]<br />
* October 25th: Virginia Tech Regional Mathematics Contest<br />
* October 29th: Review of this year's Virginia Tech contest<br />
* November 5th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/06-inequalities.pdf Inequalities] and [http://www.math.cmu.edu/~lohp/docs/math/2014-295/05-functional.pdf functional equations]<br />
* November 12th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/02-polynomials.pdf Polynomials]<br />
* November 19th: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/10-combinatorics.pdf Combinatorics]<br />
* December 3rd: [http://www.math.cmu.edu/~lohp/docs/math/2014-295/08-recursions.pdf Recursions]<br />
* December 6th: Putnam competition: Morning session: 9am-12pm, Afternoon session: 2pm-5pm in Van Vleck B119<br />
* December 10th: Review of [http://www.artofproblemsolving.com/Forum/resources/files/undergraduate_competitions/Undergraduate_Competitions-Putnam-2014-23 this year's Putnam]<br />
<br />
==Fall 2013==<br />
<br />
<br />
* September 11: [[Media:Putnam091113.pdf | Introductory Meeting]]<br />
* September 18: [[Media:Putnam091813.pdf | Assorted Problems]] (by Yihe Dong) <br />
* September 25: [[Media:Putnam092513.pdf | Combinatorics]]<br />
* October 2: [[Media:Putnam100213.pdf | Matrices and Linear Algebra]]<br />
* October 9: [[Media:Putnam100913.pdf | Number Theory]]<br />
* October 16: [[Media:Putnam101613.pdf | Functions and Calculus]]<br />
* October 23: [[Media:Putnam102313.pdf | Polynomials]]<br />
* October 26: Virginia Tech Regional Mathematics Contest<br />
* October 30: [[Media:VTRMC13.pdf | Problems from this year's Virginia Tech contest]]<br />
* November 6: [[Media:Putnam110413.pdf | Games]]<br />
* November 13: [[Media:Putnam111113.pdf | Pigeonhole Principle]]<br />
* November 20: [[Media:Putnam112013.pdf | Extreme Principle]]<br />
* November 27: No meeting (Thanksgiving)<br />
* December 4: TBA<br />
* December 7: Putnam competition Morning session: 9am-12pm, afternoon session: 2-5pm in VV B239.<br />
<br />
==Fall 2012==<br />
<br />
* September 11: Introduction [[Media:Putnam2012IntroProblems.pdf | Problems]]<br />
* September 18: Some Basic Techniques [[Media:Putnam2012Week1Problems.pdf | Problems]]<br />
* September 25: Polynomials and Algebra [[Media:Putnam2012Week2Problems.pdf | Problems]]<br />
* October 2: Number Theory [[Media:Putnam2012Week3Problems.pdf | Problems]]<br />
* October 9: Calculus [[Media:Putnam2012Week4Problems.pdf | Problems]]<br />
* October 16: Games and Algorithms [[Media:Putnam2012Week5Problems.pdf | Problems]]<br />
* October 23: Combinatorics [[Media:Putnam2012Week6Problems.pdf | Problems]]<br />
* October 30: Probability [[Media:Putnam2012Week7Problems.pdf | Problems]]<br />
* November 6: Linear Algebra [[Media:Putnam2012Week8Problems.pdf | Problems]]<br />
* November 13: Grab Bag [[Media:Putnam2012Week9Problems.pdf | Problems]]<br />
* November 27: Grab Bag 2 [[Media:Putnam2012Week10Problems.pdf | Problems]]<br />
<br />
==Fall 2011==<br />
<br />
* September 21: Pigeonhole Principle (Brian Rice) [[Media:PutnamProblemsSept21.pdf | Problems]]<br />
* September 28: Introduction to Counting (Brian Rice) [[Media:PutnamProblemsSept28.pdf | Problems]]<br />
* October 5: Elementary Number Theory (Brian Rice) [[Media:PutnamProblemsOct5.pdf | Problems]], [[Media:PutnamProblemsOct5Hard.pdf | Problems (Hardcore)]]<br />
* October 12: Polynomials (Brian Rice) [[Media:PutnamProblemsOct12.pdf | Problems]], [[Media:PutnamProblemsOct12Hard.pdf | Problems (Hardcore)]]<br />
* October 19: A Grab Bag of Discrete Math (Brian Rice) [[Media:PutnamProblemsOct19.pdf | Problems]]<br />
* October 26: Calculus, Week 1 (Brian Rice) [[Media:PutnamProblemsOct26.pdf | Problems]]<br />
* November 2: Calculus, Week 2 (Brian Rice) [[Media:PutnamProblemsNov2.pdf | Problems]]<br />
* November 9: Linear and Abstract Algebra (Brian Rice) [[Media: PutnamProblemsNov9.pdf | Problems]]<br />
* November 16: Mock Putnam [[Media: MockPutnamProblems.pdf | Problems]], [[Media: MockPutnamSolutions.pdf | Solutions]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall18&diff=15299Colloquia/Fall182018-03-27T15:56:00Z<p>Craciun: </p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
== Spring 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|January 29 (Monday)<br />
| [http://www.math.columbia.edu/~chaoli/ Li Chao] (Columbia)<br />
|[[#January 29 Li Chao (Columbia)| Elliptic curves and Goldfeld's conjecture ]]<br />
| Jordan Ellenberg<br />
|<br />
|-<br />
|February 2 (Room: 911)<br />
| [https://scholar.harvard.edu/tfai/home Thomas Fai] (Harvard)<br />
|[[#February 2 Thomas Fai (Harvard)| The Lubricated Immersed Boundary Method ]]<br />
| Spagnolie, Smith<br />
|<br />
|-<br />
|February 5 (Monday, Room: 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 5 Alex Lubotzky (Hebrew University)| High dimensional expanders: From Ramanujan graphs to Ramanujan complexes ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 6 (Tuesday 2 pm, Room 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 6 Alex Lubotzky (Hebrew University)| Groups' approximation, stability and high dimensional expanders ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 9<br />
| [http://www.math.cmu.edu/~wes/ Wes Pegden] (CMU)<br />
|[[#February 9 Wes Pegden (CMU)| The fractal nature of the Abelian Sandpile ]]<br />
| Roch<br />
|<br />
|-<br />
|March 2<br />
| [http://www.math.utah.edu/~bertram/ Aaron Bertram] (University of Utah)<br />
|[[#March 2 Aaron Bertram (Utah)| Stability in Algebraic Geometry ]]<br />
| Caldararu<br />
|<br />
|-<br />
| March 16 (Room: 911)<br />
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)<br />
|[[#March 16 Anne Gelb (Dartmouth)| Reducing the effects of bad data measurements using variance based weighted joint sparsity ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 5 (Thursday)<br />
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)<br />
|[[#April 5 John Baez (UC Riverside)| Monoidal categories of networks ]]<br />
| Craciun<br />
|<br />
|-<br />
| April 6<br />
| [https://www.math.purdue.edu/~egoins Edray Goins] (Purdue)<br />
|[[# Edray Goins| Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups ]]<br />
| Melanie<br />
|<br />
|-<br />
| April 13<br />
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 16 (Monday)<br />
| [http://www-users.math.umn.edu/~cberkesc/ Christine Berkesch Zamaere ] (University of Minnesota)<br />
|[[# TBA| TBA ]]<br />
| Erman, Sam<br />
|<br />
|-<br />
| April 25 (Wednesday)<br />
| [http://www.f.waseda.jp/hitoshi.ishii/ Hitoshi Ishii] (Waseda University) Wasow lecture<br />
|[[# TBA| TBA ]]<br />
| Tran<br />
|<br />
|-<br />
| May 4<br />
| [http://math.mit.edu/~cohn/ Henry Cohn] (Microsoft Research and MIT)<br />
|[[# TBA| TBA ]]<br />
| Ellenberg<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
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|[[# TBA| TBA ]]<br />
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|}<br />
<br />
== Spring Abstracts ==<br />
<br />
<br />
===January 29 Li Chao (Columbia)===<br />
<br />
Title: Elliptic curves and Goldfeld's conjecture<br />
<br />
Abstract: <br />
An elliptic curve is a plane curve defined by a cubic equation. Determining whether such an equation has infinitely many rational solutions has been a central problem in number theory for centuries, which lead to the celebrated conjecture of Birch and Swinnerton-Dyer. Within a family of elliptic curves (such as the Mordell curve family y^2=x^3-d), a conjecture of Goldfeld further predicts that there should be infinitely many rational solutions exactly half of the time. We will start with a history of this problem, discuss our recent work (with D. Kriz) towards Goldfeld's conjecture and illustrate the key ideas and ingredients behind these new progresses.<br />
<br />
=== February 2 Thomas Fai (Harvard) ===<br />
<br />
Title: The Lubricated Immersed Boundary Method<br />
<br />
Abstract:<br />
Many real-world examples of fluid-structure interaction, including the transit of red blood cells through the narrow slits in the spleen, involve the near-contact of elastic structures separated by thin layers of fluid. The separation of length scales between these fine lubrication layers and the larger elastic objects poses significant computational challenges. Motivated by the challenge of resolving such multiscale problems, we introduce an immersed boundary method that uses elements of lubrication theory to resolve thin fluid layers between immersed boundaries. We apply this method to two-dimensional flows of increasing complexity, including eccentric rotating cylinders and elastic vesicles near walls in shear flow, to show its increased accuracy compared to the classical immersed boundary method. We present preliminary simulation results of cell suspensions, a problem in which near-contact occurs at multiple levels, such as cell-wall, cell-cell, and intracellular interactions, to highlight the importance of resolving thin fluid layers in order to obtain the correct overall dynamics.<br />
<br />
===February 5 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: High dimensional expanders: From Ramanujan graphs to Ramanujan complexes<br />
<br />
Abstract: <br />
<br />
Expander graphs in general, and Ramanujan graphs , in particular, have played a major role in computer science in the last 5 decades and more recently also in pure math. The first explicit construction of bounded degree expanding graphs was given by Margulis in the early 70's. In mid 80' Margulis and Lubotzky-Phillips-Sarnak provided Ramanujan graphs which are optimal such expanders. <br />
<br />
In recent years a high dimensional theory of expanders is emerging. A notion of topological expanders was defined by Gromov in 2010 who proved that the complete d-dimensional simplical complexes are such. He raised the basic question of existence of such bounded degree complexes of dimension d>1. <br />
<br />
This question was answered recently affirmatively (by T. Kaufman, D. Kazdhan and A. Lubotzky for d=2 and by S. Evra and T. Kaufman for general d) by showing that the d-skeleton of (d+1)-dimensional Ramanujan complexes provide such topological expanders. We will describe these developments and the general area of high dimensional expanders. <br />
<br />
<br />
===February 6 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: Groups' approximation, stability and high dimensional expanders<br />
<br />
Abstract: <br />
<br />
Several well-known open questions, such as: are all groups sofic or hyperlinear?, have a common form: can all groups be approximated by asymptotic homomorphisms into the symmetric groups Sym(n) (in the sofic case) or the unitary groups U(n) (in the hyperlinear case)? In the case of U(n), the question can be asked with respect to different metrics and norms. We answer, for the first time, one of these versions, showing that there exist fintely presented groups which are not approximated by U(n) with respect to the Frobenius (=L_2) norm.<br />
<br />
The strategy is via the notion of "stability": some higher dimensional cohomology vanishing phenomena is proven to imply stability and using high dimensional expanders, it is shown that some non-residually finite groups (central extensions of some lattices in p-adic Lie groups) are Frobenious stable and hence cannot be Frobenius approximated. <br />
<br />
All notions will be explained. Joint work with M, De Chiffre, L. Glebsky and A. Thom.<br />
<br />
===February 9 Wes Pegden (CMU)===<br />
<br />
Title: The fractal nature of the Abelian Sandpile <br />
<br />
Abstract: The Abelian Sandpile is a simple diffusion process on the integer lattice, in which configurations of chips disperse according to a simple rule: when a vertex has at least 4 chips, it can distribute one chip to each neighbor. <br />
<br />
Introduced in the statistical physics community in the 1980s, the Abelian sandpile exhibits striking fractal behavior which long resisted rigorous mathematical analysis (or even a plausible explanation). We now have a relatively robust mathematical understanding of this fractal nature of the sandpile, which involves surprising connections between integer superharmonic functions on the lattice, discrete tilings of the plane, and Apollonian circle packings. In this talk, we will survey our work in this area, and discuss avenues of current and future research.<br />
<br />
===March 2 Aaron Bertram (Utah)===<br />
<br />
Title: Stability in Algebraic Geometry<br />
<br />
Abstract: Stability was originally introduced in algebraic geometry in the context of finding a projective quotient space for the action of an algebraic group on a projective manifold. This, in turn, led in the 1960s to a notion of slope-stability for vector bundles on a Riemann surface, which was an important tool in the classification of vector bundles. In the 1990s, mirror symmetry considerations led Michael Douglas to notions of stability for "D-branes" (on a higher-dimensional manifold) that corresponded to no previously known mathematical definition. We now understand each of these notions of stability as a distinct point of a complex "stability manifold" that is an important invariant of the (derived) category of complexes of vector bundles of a projective manifold. In this talk I want to give some examples to illustrate the various stabilities, and also to describe some current work in the area.<br />
<br />
===March 16 Anne Gelb (Dartmouth)===<br />
<br />
Title: Reducing the effects of bad data measurements using variance based weighted joint sparsity<br />
<br />
Abstract: We introduce the variance based joint sparsity (VBJS) method for sparse signal recovery and image reconstruction from multiple measurement vectors. Joint sparsity techniques employing $\ell_{2,1}$ minimization are typically used, but the algorithm is computationally intensive and requires fine tuning of parameters. The VBJS method uses a weighted $\ell_1$ joint sparsity algorithm, where the weights depend on the pixel-wise variance. The VBJS method is accurate, robust, cost efficient and also reduces the effects of false data.<br />
<br />
<br />
<br />
<br />
===April 5 John Baez (UC Riverside)===<br />
<br />
Title: Monoidal categories of networks<br />
<br />
Abstract: Nature and the world of human technology are full of networks. People like to draw diagrams of networks: flow charts, electrical circuit diagrams, chemical reaction networks, signal-flow graphs, Bayesian networks, food webs, Feynman diagrams and the like. Far from mere informal tools, many of these diagrammatic languages fit into a rigorous framework: category theory. I will explain a bit of how this works and discuss some applications.<br />
<br />
<br />
<br />
<br />
<br />
===April 6 Edray Goins (Purdue)===<br />
<br />
Title: Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups<br />
<br />
Abstract: A Bely&#301; map <math> \beta: \mathbb P^1(\mathbb C) \to \mathbb P^1(\mathbb C) </math> is a rational function with at most three critical values; we may assume these values are <math> \{ 0, \, 1, \, \infty \}. </math> A Dessin d'Enfant is a planar bipartite graph obtained by considering the preimage of a path between two of these critical values, usually taken to be the line segment from 0 to 1. Such graphs can be drawn on the sphere by composing with stereographic projection: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq \mathbb P^1(\mathbb C) \simeq S^2(\mathbb R). </math> Replacing <math> \mathbb P^1 </math> with an elliptic curve <math>E </math>, there is a similar definition of a Bely&#301; map <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C). </math> Since <math> E(\mathbb C) \simeq \mathbb T^2(\mathbb R) </math> is a torus, we call <math> (E, \beta) </math> a toroidal Bely&#301; pair. The corresponding Dessin d'Enfant can be drawn on the torus by composing with an elliptic logarithm: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq E(\mathbb C) \simeq \mathbb T^2(\mathbb R). </math><br />
<br />
This project seeks to create a database of such Bely&#301; pairs, their corresponding Dessins d'Enfant, and their monodromy groups. For each positive integer <math> N </math>, there are only finitely many toroidal Bely&#301; pairs <math> (E, \beta) </math> with <math> \deg \, \beta = N. </math> Using the Hurwitz Genus formula, we can begin this database by considering all possible degree sequences <math> \mathcal D </math> on the ramification indices as multisets on three partitions of N. For each degree sequence, we compute all possible monodromy groups <math> G = \text{im} \, \bigl[ \pi_1 \bigl( \mathbb P^1(\mathbb C) - \{ 0, \, 1, \, \infty \} \bigr) \to S_N \bigr]; </math> they are the ``Galois closure'' of the group of automorphisms of the graph. Finally, for each possible monodromy group, we compute explicit formulas for Bely&#301; maps <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C) </math> associated to some elliptic curve <math> E: \ y^2 = x^3 + A \, x + B. </math> We will discuss some of the challenges of determining the structure of these groups, and present visualizations of group actions on the torus. <br />
<br />
This work is part of PRiME (Purdue Research in Mathematics Experience) with Chineze Christopher, Robert Dicks, Gina Ferolito, Joseph Sauder, and Danika Van Niel with assistance by Edray Goins and Abhishek Parab.<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank Colloquia]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall18&diff=15298Colloquia/Fall182018-03-27T15:54:44Z<p>Craciun: /* April 5 John Baez (UC Riverside) */</p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
== Spring 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|January 29 (Monday)<br />
| [http://www.math.columbia.edu/~chaoli/ Li Chao] (Columbia)<br />
|[[#January 29 Li Chao (Columbia)| Elliptic curves and Goldfeld's conjecture ]]<br />
| Jordan Ellenberg<br />
|<br />
|-<br />
|February 2 (Room: 911)<br />
| [https://scholar.harvard.edu/tfai/home Thomas Fai] (Harvard)<br />
|[[#February 2 Thomas Fai (Harvard)| The Lubricated Immersed Boundary Method ]]<br />
| Spagnolie, Smith<br />
|<br />
|-<br />
|February 5 (Monday, Room: 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 5 Alex Lubotzky (Hebrew University)| High dimensional expanders: From Ramanujan graphs to Ramanujan complexes ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 6 (Tuesday 2 pm, Room 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 6 Alex Lubotzky (Hebrew University)| Groups' approximation, stability and high dimensional expanders ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 9<br />
| [http://www.math.cmu.edu/~wes/ Wes Pegden] (CMU)<br />
|[[#February 9 Wes Pegden (CMU)| The fractal nature of the Abelian Sandpile ]]<br />
| Roch<br />
|<br />
|-<br />
|March 2<br />
| [http://www.math.utah.edu/~bertram/ Aaron Bertram] (University of Utah)<br />
|[[#March 2 Aaron Bertram (Utah)| Stability in Algebraic Geometry ]]<br />
| Caldararu<br />
|<br />
|-<br />
| March 16 (Room: 911)<br />
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)<br />
|[[#March 16 Anne Gelb (Dartmouth)| Reducing the effects of bad data measurements using variance based weighted joint sparsity ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 5 (Thursday)<br />
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)<br />
|[[#April 5 John Baez (UC Riverside)| Monoidal categories of networks ]]<br />
| Craciun<br />
|<br />
|-<br />
| April 6<br />
| [https://www.math.purdue.edu/~egoins Edray Goins] (Purdue)<br />
|[[# Edray Goins| Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups ]]<br />
| Melanie<br />
|<br />
|-<br />
| April 13<br />
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 16 (Monday)<br />
| [http://www-users.math.umn.edu/~cberkesc/ Christine Berkesch Zamaere ] (University of Minnesota)<br />
|[[# TBA| TBA ]]<br />
| Erman, Sam<br />
|<br />
|-<br />
| April 25 (Wednesday)<br />
| [http://www.f.waseda.jp/hitoshi.ishii/ Hitoshi Ishii] (Waseda University) Wasow lecture<br />
|[[# TBA| TBA ]]<br />
| Tran<br />
|<br />
|-<br />
| May 4<br />
| [http://math.mit.edu/~cohn/ Henry Cohn] (Microsoft Research and MIT)<br />
|[[# TBA| TBA ]]<br />
| Ellenberg<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
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|[[# TBA| TBA ]]<br />
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|<br />
|-<br />
|date<br />
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|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
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|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
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|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
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|<br />
|-<br />
|date<br />
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|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|}<br />
<br />
== Spring Abstracts ==<br />
<br />
<br />
===January 29 Li Chao (Columbia)===<br />
<br />
Title: Elliptic curves and Goldfeld's conjecture<br />
<br />
Abstract: <br />
An elliptic curve is a plane curve defined by a cubic equation. Determining whether such an equation has infinitely many rational solutions has been a central problem in number theory for centuries, which lead to the celebrated conjecture of Birch and Swinnerton-Dyer. Within a family of elliptic curves (such as the Mordell curve family y^2=x^3-d), a conjecture of Goldfeld further predicts that there should be infinitely many rational solutions exactly half of the time. We will start with a history of this problem, discuss our recent work (with D. Kriz) towards Goldfeld's conjecture and illustrate the key ideas and ingredients behind these new progresses.<br />
<br />
=== February 2 Thomas Fai (Harvard) ===<br />
<br />
Title: The Lubricated Immersed Boundary Method<br />
<br />
Abstract:<br />
Many real-world examples of fluid-structure interaction, including the transit of red blood cells through the narrow slits in the spleen, involve the near-contact of elastic structures separated by thin layers of fluid. The separation of length scales between these fine lubrication layers and the larger elastic objects poses significant computational challenges. Motivated by the challenge of resolving such multiscale problems, we introduce an immersed boundary method that uses elements of lubrication theory to resolve thin fluid layers between immersed boundaries. We apply this method to two-dimensional flows of increasing complexity, including eccentric rotating cylinders and elastic vesicles near walls in shear flow, to show its increased accuracy compared to the classical immersed boundary method. We present preliminary simulation results of cell suspensions, a problem in which near-contact occurs at multiple levels, such as cell-wall, cell-cell, and intracellular interactions, to highlight the importance of resolving thin fluid layers in order to obtain the correct overall dynamics.<br />
<br />
===February 5 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: High dimensional expanders: From Ramanujan graphs to Ramanujan complexes<br />
<br />
Abstract: <br />
<br />
Expander graphs in general, and Ramanujan graphs , in particular, have played a major role in computer science in the last 5 decades and more recently also in pure math. The first explicit construction of bounded degree expanding graphs was given by Margulis in the early 70's. In mid 80' Margulis and Lubotzky-Phillips-Sarnak provided Ramanujan graphs which are optimal such expanders. <br />
<br />
In recent years a high dimensional theory of expanders is emerging. A notion of topological expanders was defined by Gromov in 2010 who proved that the complete d-dimensional simplical complexes are such. He raised the basic question of existence of such bounded degree complexes of dimension d>1. <br />
<br />
This question was answered recently affirmatively (by T. Kaufman, D. Kazdhan and A. Lubotzky for d=2 and by S. Evra and T. Kaufman for general d) by showing that the d-skeleton of (d+1)-dimensional Ramanujan complexes provide such topological expanders. We will describe these developments and the general area of high dimensional expanders. <br />
<br />
<br />
===February 6 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: Groups' approximation, stability and high dimensional expanders<br />
<br />
Abstract: <br />
<br />
Several well-known open questions, such as: are all groups sofic or hyperlinear?, have a common form: can all groups be approximated by asymptotic homomorphisms into the symmetric groups Sym(n) (in the sofic case) or the unitary groups U(n) (in the hyperlinear case)? In the case of U(n), the question can be asked with respect to different metrics and norms. We answer, for the first time, one of these versions, showing that there exist fintely presented groups which are not approximated by U(n) with respect to the Frobenius (=L_2) norm.<br />
<br />
The strategy is via the notion of "stability": some higher dimensional cohomology vanishing phenomena is proven to imply stability and using high dimensional expanders, it is shown that some non-residually finite groups (central extensions of some lattices in p-adic Lie groups) are Frobenious stable and hence cannot be Frobenius approximated. <br />
<br />
All notions will be explained. Joint work with M, De Chiffre, L. Glebsky and A. Thom.<br />
<br />
===February 9 Wes Pegden (CMU)===<br />
<br />
Title: The fractal nature of the Abelian Sandpile <br />
<br />
Abstract: The Abelian Sandpile is a simple diffusion process on the integer lattice, in which configurations of chips disperse according to a simple rule: when a vertex has at least 4 chips, it can distribute one chip to each neighbor. <br />
<br />
Introduced in the statistical physics community in the 1980s, the Abelian sandpile exhibits striking fractal behavior which long resisted rigorous mathematical analysis (or even a plausible explanation). We now have a relatively robust mathematical understanding of this fractal nature of the sandpile, which involves surprising connections between integer superharmonic functions on the lattice, discrete tilings of the plane, and Apollonian circle packings. In this talk, we will survey our work in this area, and discuss avenues of current and future research.<br />
<br />
===March 2 Aaron Bertram (Utah)===<br />
<br />
Title: Stability in Algebraic Geometry<br />
<br />
Abstract: Stability was originally introduced in algebraic geometry in the context of finding a projective quotient space for the action of an algebraic group on a projective manifold. This, in turn, led in the 1960s to a notion of slope-stability for vector bundles on a Riemann surface, which was an important tool in the classification of vector bundles. In the 1990s, mirror symmetry considerations led Michael Douglas to notions of stability for "D-branes" (on a higher-dimensional manifold) that corresponded to no previously known mathematical definition. We now understand each of these notions of stability as a distinct point of a complex "stability manifold" that is an important invariant of the (derived) category of complexes of vector bundles of a projective manifold. In this talk I want to give some examples to illustrate the various stabilities, and also to describe some current work in the area.<br />
<br />
===March 16 Anne Gelb (Dartmouth)===<br />
<br />
Title: Reducing the effects of bad data measurements using variance based weighted joint sparsity<br />
<br />
Abstract: We introduce the variance based joint sparsity (VBJS) method for sparse signal recovery and image reconstruction from multiple measurement vectors. Joint sparsity techniques employing $\ell_{2,1}$ minimization are typically used, but the algorithm is computationally intensive and requires fine tuning of parameters. The VBJS method uses a weighted $\ell_1$ joint sparsity algorithm, where the weights depend on the pixel-wise variance. The VBJS method is accurate, robust, cost efficient and also reduces the effects of false data.<br />
<br />
<br />
<br />
<br />
===April 5 John Baez (UC Riverside)===<br />
<br />
Title: Monoidal categories of networks<br />
<br />
Abstract: Nature and the world of human technology are full of networks. People like to draw diagrams of networks: flow charts, electrical circuit diagrams, chemical reaction networks, signal-flow graphs, Bayesian networks, food webs, Feynman diagrams and the like. Far from mere informal tools, many of these diagrammatic languages fit into a rigorous framework: category theory. I will explain a bit of how this works and discuss some applications.<br />
<br />
===April 6 Edray Goins (Purdue)===<br />
<br />
Title: Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups<br />
<br />
Abstract: A Bely&#301; map <math> \beta: \mathbb P^1(\mathbb C) \to \mathbb P^1(\mathbb C) </math> is a rational function with at most three critical values; we may assume these values are <math> \{ 0, \, 1, \, \infty \}. </math> A Dessin d'Enfant is a planar bipartite graph obtained by considering the preimage of a path between two of these critical values, usually taken to be the line segment from 0 to 1. Such graphs can be drawn on the sphere by composing with stereographic projection: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq \mathbb P^1(\mathbb C) \simeq S^2(\mathbb R). </math> Replacing <math> \mathbb P^1 </math> with an elliptic curve <math>E </math>, there is a similar definition of a Bely&#301; map <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C). </math> Since <math> E(\mathbb C) \simeq \mathbb T^2(\mathbb R) </math> is a torus, we call <math> (E, \beta) </math> a toroidal Bely&#301; pair. The corresponding Dessin d'Enfant can be drawn on the torus by composing with an elliptic logarithm: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq E(\mathbb C) \simeq \mathbb T^2(\mathbb R). </math><br />
<br />
This project seeks to create a database of such Bely&#301; pairs, their corresponding Dessins d'Enfant, and their monodromy groups. For each positive integer <math> N </math>, there are only finitely many toroidal Bely&#301; pairs <math> (E, \beta) </math> with <math> \deg \, \beta = N. </math> Using the Hurwitz Genus formula, we can begin this database by considering all possible degree sequences <math> \mathcal D </math> on the ramification indices as multisets on three partitions of N. For each degree sequence, we compute all possible monodromy groups <math> G = \text{im} \, \bigl[ \pi_1 \bigl( \mathbb P^1(\mathbb C) - \{ 0, \, 1, \, \infty \} \bigr) \to S_N \bigr]; </math> they are the ``Galois closure'' of the group of automorphisms of the graph. Finally, for each possible monodromy group, we compute explicit formulas for Bely&#301; maps <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C) </math> associated to some elliptic curve <math> E: \ y^2 = x^3 + A \, x + B. </math> We will discuss some of the challenges of determining the structure of these groups, and present visualizations of group actions on the torus. <br />
<br />
This work is part of PRiME (Purdue Research in Mathematics Experience) with Chineze Christopher, Robert Dicks, Gina Ferolito, Joseph Sauder, and Danika Van Niel with assistance by Edray Goins and Abhishek Parab.<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank Colloquia]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall18&diff=15297Colloquia/Fall182018-03-27T15:54:09Z<p>Craciun: </p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
== Spring 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|January 29 (Monday)<br />
| [http://www.math.columbia.edu/~chaoli/ Li Chao] (Columbia)<br />
|[[#January 29 Li Chao (Columbia)| Elliptic curves and Goldfeld's conjecture ]]<br />
| Jordan Ellenberg<br />
|<br />
|-<br />
|February 2 (Room: 911)<br />
| [https://scholar.harvard.edu/tfai/home Thomas Fai] (Harvard)<br />
|[[#February 2 Thomas Fai (Harvard)| The Lubricated Immersed Boundary Method ]]<br />
| Spagnolie, Smith<br />
|<br />
|-<br />
|February 5 (Monday, Room: 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 5 Alex Lubotzky (Hebrew University)| High dimensional expanders: From Ramanujan graphs to Ramanujan complexes ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 6 (Tuesday 2 pm, Room 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 6 Alex Lubotzky (Hebrew University)| Groups' approximation, stability and high dimensional expanders ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 9<br />
| [http://www.math.cmu.edu/~wes/ Wes Pegden] (CMU)<br />
|[[#February 9 Wes Pegden (CMU)| The fractal nature of the Abelian Sandpile ]]<br />
| Roch<br />
|<br />
|-<br />
|March 2<br />
| [http://www.math.utah.edu/~bertram/ Aaron Bertram] (University of Utah)<br />
|[[#March 2 Aaron Bertram (Utah)| Stability in Algebraic Geometry ]]<br />
| Caldararu<br />
|<br />
|-<br />
| March 16 (Room: 911)<br />
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)<br />
|[[#March 16 Anne Gelb (Dartmouth)| Reducing the effects of bad data measurements using variance based weighted joint sparsity ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 5 (Thursday)<br />
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)<br />
|[[#April 5 John Baez (UC Riverside)| Monoidal categories of networks ]]<br />
| Craciun<br />
|<br />
|-<br />
| April 6<br />
| [https://www.math.purdue.edu/~egoins Edray Goins] (Purdue)<br />
|[[# Edray Goins| Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups ]]<br />
| Melanie<br />
|<br />
|-<br />
| April 13<br />
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 16 (Monday)<br />
| [http://www-users.math.umn.edu/~cberkesc/ Christine Berkesch Zamaere ] (University of Minnesota)<br />
|[[# TBA| TBA ]]<br />
| Erman, Sam<br />
|<br />
|-<br />
| April 25 (Wednesday)<br />
| [http://www.f.waseda.jp/hitoshi.ishii/ Hitoshi Ishii] (Waseda University) Wasow lecture<br />
|[[# TBA| TBA ]]<br />
| Tran<br />
|<br />
|-<br />
| May 4<br />
| [http://math.mit.edu/~cohn/ Henry Cohn] (Microsoft Research and MIT)<br />
|[[# TBA| TBA ]]<br />
| Ellenberg<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|}<br />
<br />
== Spring Abstracts ==<br />
<br />
<br />
===January 29 Li Chao (Columbia)===<br />
<br />
Title: Elliptic curves and Goldfeld's conjecture<br />
<br />
Abstract: <br />
An elliptic curve is a plane curve defined by a cubic equation. Determining whether such an equation has infinitely many rational solutions has been a central problem in number theory for centuries, which lead to the celebrated conjecture of Birch and Swinnerton-Dyer. Within a family of elliptic curves (such as the Mordell curve family y^2=x^3-d), a conjecture of Goldfeld further predicts that there should be infinitely many rational solutions exactly half of the time. We will start with a history of this problem, discuss our recent work (with D. Kriz) towards Goldfeld's conjecture and illustrate the key ideas and ingredients behind these new progresses.<br />
<br />
=== February 2 Thomas Fai (Harvard) ===<br />
<br />
Title: The Lubricated Immersed Boundary Method<br />
<br />
Abstract:<br />
Many real-world examples of fluid-structure interaction, including the transit of red blood cells through the narrow slits in the spleen, involve the near-contact of elastic structures separated by thin layers of fluid. The separation of length scales between these fine lubrication layers and the larger elastic objects poses significant computational challenges. Motivated by the challenge of resolving such multiscale problems, we introduce an immersed boundary method that uses elements of lubrication theory to resolve thin fluid layers between immersed boundaries. We apply this method to two-dimensional flows of increasing complexity, including eccentric rotating cylinders and elastic vesicles near walls in shear flow, to show its increased accuracy compared to the classical immersed boundary method. We present preliminary simulation results of cell suspensions, a problem in which near-contact occurs at multiple levels, such as cell-wall, cell-cell, and intracellular interactions, to highlight the importance of resolving thin fluid layers in order to obtain the correct overall dynamics.<br />
<br />
===February 5 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: High dimensional expanders: From Ramanujan graphs to Ramanujan complexes<br />
<br />
Abstract: <br />
<br />
Expander graphs in general, and Ramanujan graphs , in particular, have played a major role in computer science in the last 5 decades and more recently also in pure math. The first explicit construction of bounded degree expanding graphs was given by Margulis in the early 70's. In mid 80' Margulis and Lubotzky-Phillips-Sarnak provided Ramanujan graphs which are optimal such expanders. <br />
<br />
In recent years a high dimensional theory of expanders is emerging. A notion of topological expanders was defined by Gromov in 2010 who proved that the complete d-dimensional simplical complexes are such. He raised the basic question of existence of such bounded degree complexes of dimension d>1. <br />
<br />
This question was answered recently affirmatively (by T. Kaufman, D. Kazdhan and A. Lubotzky for d=2 and by S. Evra and T. Kaufman for general d) by showing that the d-skeleton of (d+1)-dimensional Ramanujan complexes provide such topological expanders. We will describe these developments and the general area of high dimensional expanders. <br />
<br />
<br />
===February 6 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: Groups' approximation, stability and high dimensional expanders<br />
<br />
Abstract: <br />
<br />
Several well-known open questions, such as: are all groups sofic or hyperlinear?, have a common form: can all groups be approximated by asymptotic homomorphisms into the symmetric groups Sym(n) (in the sofic case) or the unitary groups U(n) (in the hyperlinear case)? In the case of U(n), the question can be asked with respect to different metrics and norms. We answer, for the first time, one of these versions, showing that there exist fintely presented groups which are not approximated by U(n) with respect to the Frobenius (=L_2) norm.<br />
<br />
The strategy is via the notion of "stability": some higher dimensional cohomology vanishing phenomena is proven to imply stability and using high dimensional expanders, it is shown that some non-residually finite groups (central extensions of some lattices in p-adic Lie groups) are Frobenious stable and hence cannot be Frobenius approximated. <br />
<br />
All notions will be explained. Joint work with M, De Chiffre, L. Glebsky and A. Thom.<br />
<br />
===February 9 Wes Pegden (CMU)===<br />
<br />
Title: The fractal nature of the Abelian Sandpile <br />
<br />
Abstract: The Abelian Sandpile is a simple diffusion process on the integer lattice, in which configurations of chips disperse according to a simple rule: when a vertex has at least 4 chips, it can distribute one chip to each neighbor. <br />
<br />
Introduced in the statistical physics community in the 1980s, the Abelian sandpile exhibits striking fractal behavior which long resisted rigorous mathematical analysis (or even a plausible explanation). We now have a relatively robust mathematical understanding of this fractal nature of the sandpile, which involves surprising connections between integer superharmonic functions on the lattice, discrete tilings of the plane, and Apollonian circle packings. In this talk, we will survey our work in this area, and discuss avenues of current and future research.<br />
<br />
===March 2 Aaron Bertram (Utah)===<br />
<br />
Title: Stability in Algebraic Geometry<br />
<br />
Abstract: Stability was originally introduced in algebraic geometry in the context of finding a projective quotient space for the action of an algebraic group on a projective manifold. This, in turn, led in the 1960s to a notion of slope-stability for vector bundles on a Riemann surface, which was an important tool in the classification of vector bundles. In the 1990s, mirror symmetry considerations led Michael Douglas to notions of stability for "D-branes" (on a higher-dimensional manifold) that corresponded to no previously known mathematical definition. We now understand each of these notions of stability as a distinct point of a complex "stability manifold" that is an important invariant of the (derived) category of complexes of vector bundles of a projective manifold. In this talk I want to give some examples to illustrate the various stabilities, and also to describe some current work in the area.<br />
<br />
===March 16 Anne Gelb (Dartmouth)===<br />
<br />
Title: Reducing the effects of bad data measurements using variance based weighted joint sparsity<br />
<br />
Abstract: We introduce the variance based joint sparsity (VBJS) method for sparse signal recovery and image reconstruction from multiple measurement vectors. Joint sparsity techniques employing $\ell_{2,1}$ minimization are typically used, but the algorithm is computationally intensive and requires fine tuning of parameters. The VBJS method uses a weighted $\ell_1$ joint sparsity algorithm, where the weights depend on the pixel-wise variance. The VBJS method is accurate, robust, cost efficient and also reduces the effects of false data.<br />
<br />
<br />
<br />
<br />
===April 5 John Baez (UC Riverside)===<br />
<br />
Title: Reducing the effects of bad data measurements using variance based weighted joint sparsity<br />
<br />
Abstract: Nature and the world of human technology are full of networks. People like to draw diagrams of networks: flow charts, electrical circuit diagrams, chemical reaction networks, signal-flow graphs, Bayesian networks, food webs, Feynman diagrams and the like. Far from mere informal tools, many of these diagrammatic languages fit into a rigorous framework: category theory. I will explain a bit of how this works and discuss some applications. <br />
<br />
<br />
<br />
<br />
<br />
===April 6 Edray Goins (Purdue)===<br />
<br />
Title: Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups<br />
<br />
Abstract: A Bely&#301; map <math> \beta: \mathbb P^1(\mathbb C) \to \mathbb P^1(\mathbb C) </math> is a rational function with at most three critical values; we may assume these values are <math> \{ 0, \, 1, \, \infty \}. </math> A Dessin d'Enfant is a planar bipartite graph obtained by considering the preimage of a path between two of these critical values, usually taken to be the line segment from 0 to 1. Such graphs can be drawn on the sphere by composing with stereographic projection: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq \mathbb P^1(\mathbb C) \simeq S^2(\mathbb R). </math> Replacing <math> \mathbb P^1 </math> with an elliptic curve <math>E </math>, there is a similar definition of a Bely&#301; map <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C). </math> Since <math> E(\mathbb C) \simeq \mathbb T^2(\mathbb R) </math> is a torus, we call <math> (E, \beta) </math> a toroidal Bely&#301; pair. The corresponding Dessin d'Enfant can be drawn on the torus by composing with an elliptic logarithm: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq E(\mathbb C) \simeq \mathbb T^2(\mathbb R). </math><br />
<br />
This project seeks to create a database of such Bely&#301; pairs, their corresponding Dessins d'Enfant, and their monodromy groups. For each positive integer <math> N </math>, there are only finitely many toroidal Bely&#301; pairs <math> (E, \beta) </math> with <math> \deg \, \beta = N. </math> Using the Hurwitz Genus formula, we can begin this database by considering all possible degree sequences <math> \mathcal D </math> on the ramification indices as multisets on three partitions of N. For each degree sequence, we compute all possible monodromy groups <math> G = \text{im} \, \bigl[ \pi_1 \bigl( \mathbb P^1(\mathbb C) - \{ 0, \, 1, \, \infty \} \bigr) \to S_N \bigr]; </math> they are the ``Galois closure'' of the group of automorphisms of the graph. Finally, for each possible monodromy group, we compute explicit formulas for Bely&#301; maps <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C) </math> associated to some elliptic curve <math> E: \ y^2 = x^3 + A \, x + B. </math> We will discuss some of the challenges of determining the structure of these groups, and present visualizations of group actions on the torus. <br />
<br />
This work is part of PRiME (Purdue Research in Mathematics Experience) with Chineze Christopher, Robert Dicks, Gina Ferolito, Joseph Sauder, and Danika Van Niel with assistance by Edray Goins and Abhishek Parab.<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank Colloquia]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall18&diff=15296Colloquia/Fall182018-03-27T15:51:37Z<p>Craciun: </p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
== Spring 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|January 29 (Monday)<br />
| [http://www.math.columbia.edu/~chaoli/ Li Chao] (Columbia)<br />
|[[#January 29 Li Chao (Columbia)| Elliptic curves and Goldfeld's conjecture ]]<br />
| Jordan Ellenberg<br />
|<br />
|-<br />
|February 2 (Room: 911)<br />
| [https://scholar.harvard.edu/tfai/home Thomas Fai] (Harvard)<br />
|[[#February 2 Thomas Fai (Harvard)| The Lubricated Immersed Boundary Method ]]<br />
| Spagnolie, Smith<br />
|<br />
|-<br />
|February 5 (Monday, Room: 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 5 Alex Lubotzky (Hebrew University)| High dimensional expanders: From Ramanujan graphs to Ramanujan complexes ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 6 (Tuesday 2 pm, Room 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 6 Alex Lubotzky (Hebrew University)| Groups' approximation, stability and high dimensional expanders ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 9<br />
| [http://www.math.cmu.edu/~wes/ Wes Pegden] (CMU)<br />
|[[#February 9 Wes Pegden (CMU)| The fractal nature of the Abelian Sandpile ]]<br />
| Roch<br />
|<br />
|-<br />
|March 2<br />
| [http://www.math.utah.edu/~bertram/ Aaron Bertram] (University of Utah)<br />
|[[#March 2 Aaron Bertram (Utah)| Stability in Algebraic Geometry ]]<br />
| Caldararu<br />
|<br />
|-<br />
| March 16 (Room: 911)<br />
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)<br />
|[[#March 16 Anne Gelb (Dartmouth)| Reducing the effects of bad data measurements using variance based weighted joint sparsity ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 5 (Thursday)<br />
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)<br />
|[[#April 5 John Baez (UC Riverside)| Monoidal categories of networks ]]<br />
| Craciun<br />
|<br />
|-<br />
| April 6<br />
| [https://www.math.purdue.edu/~egoins Edray Goins] (Purdue)<br />
|[[# Edray Goins| Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups ]]<br />
| Melanie<br />
|<br />
|-<br />
| April 13<br />
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 16 (Monday)<br />
| [http://www-users.math.umn.edu/~cberkesc/ Christine Berkesch Zamaere ] (University of Minnesota)<br />
|[[# TBA| TBA ]]<br />
| Erman, Sam<br />
|<br />
|-<br />
| April 25 (Wednesday)<br />
| [http://www.f.waseda.jp/hitoshi.ishii/ Hitoshi Ishii] (Waseda University) Wasow lecture<br />
|[[# TBA| TBA ]]<br />
| Tran<br />
|<br />
|-<br />
| May 4<br />
| [http://math.mit.edu/~cohn/ Henry Cohn] (Microsoft Research and MIT)<br />
|[[# TBA| TBA ]]<br />
| Ellenberg<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|}<br />
<br />
== Spring Abstracts ==<br />
<br />
<br />
===January 29 Li Chao (Columbia)===<br />
<br />
Title: Elliptic curves and Goldfeld's conjecture<br />
<br />
Abstract: <br />
An elliptic curve is a plane curve defined by a cubic equation. Determining whether such an equation has infinitely many rational solutions has been a central problem in number theory for centuries, which lead to the celebrated conjecture of Birch and Swinnerton-Dyer. Within a family of elliptic curves (such as the Mordell curve family y^2=x^3-d), a conjecture of Goldfeld further predicts that there should be infinitely many rational solutions exactly half of the time. We will start with a history of this problem, discuss our recent work (with D. Kriz) towards Goldfeld's conjecture and illustrate the key ideas and ingredients behind these new progresses.<br />
<br />
=== February 2 Thomas Fai (Harvard) ===<br />
<br />
Title: The Lubricated Immersed Boundary Method<br />
<br />
Abstract:<br />
Many real-world examples of fluid-structure interaction, including the transit of red blood cells through the narrow slits in the spleen, involve the near-contact of elastic structures separated by thin layers of fluid. The separation of length scales between these fine lubrication layers and the larger elastic objects poses significant computational challenges. Motivated by the challenge of resolving such multiscale problems, we introduce an immersed boundary method that uses elements of lubrication theory to resolve thin fluid layers between immersed boundaries. We apply this method to two-dimensional flows of increasing complexity, including eccentric rotating cylinders and elastic vesicles near walls in shear flow, to show its increased accuracy compared to the classical immersed boundary method. We present preliminary simulation results of cell suspensions, a problem in which near-contact occurs at multiple levels, such as cell-wall, cell-cell, and intracellular interactions, to highlight the importance of resolving thin fluid layers in order to obtain the correct overall dynamics.<br />
<br />
===February 5 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: High dimensional expanders: From Ramanujan graphs to Ramanujan complexes<br />
<br />
Abstract: <br />
<br />
Expander graphs in general, and Ramanujan graphs , in particular, have played a major role in computer science in the last 5 decades and more recently also in pure math. The first explicit construction of bounded degree expanding graphs was given by Margulis in the early 70's. In mid 80' Margulis and Lubotzky-Phillips-Sarnak provided Ramanujan graphs which are optimal such expanders. <br />
<br />
In recent years a high dimensional theory of expanders is emerging. A notion of topological expanders was defined by Gromov in 2010 who proved that the complete d-dimensional simplical complexes are such. He raised the basic question of existence of such bounded degree complexes of dimension d>1. <br />
<br />
This question was answered recently affirmatively (by T. Kaufman, D. Kazdhan and A. Lubotzky for d=2 and by S. Evra and T. Kaufman for general d) by showing that the d-skeleton of (d+1)-dimensional Ramanujan complexes provide such topological expanders. We will describe these developments and the general area of high dimensional expanders. <br />
<br />
<br />
===February 6 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: Groups' approximation, stability and high dimensional expanders<br />
<br />
Abstract: <br />
<br />
Several well-known open questions, such as: are all groups sofic or hyperlinear?, have a common form: can all groups be approximated by asymptotic homomorphisms into the symmetric groups Sym(n) (in the sofic case) or the unitary groups U(n) (in the hyperlinear case)? In the case of U(n), the question can be asked with respect to different metrics and norms. We answer, for the first time, one of these versions, showing that there exist fintely presented groups which are not approximated by U(n) with respect to the Frobenius (=L_2) norm.<br />
<br />
The strategy is via the notion of "stability": some higher dimensional cohomology vanishing phenomena is proven to imply stability and using high dimensional expanders, it is shown that some non-residually finite groups (central extensions of some lattices in p-adic Lie groups) are Frobenious stable and hence cannot be Frobenius approximated. <br />
<br />
All notions will be explained. Joint work with M, De Chiffre, L. Glebsky and A. Thom.<br />
<br />
===February 9 Wes Pegden (CMU)===<br />
<br />
Title: The fractal nature of the Abelian Sandpile <br />
<br />
Abstract: The Abelian Sandpile is a simple diffusion process on the integer lattice, in which configurations of chips disperse according to a simple rule: when a vertex has at least 4 chips, it can distribute one chip to each neighbor. <br />
<br />
Introduced in the statistical physics community in the 1980s, the Abelian sandpile exhibits striking fractal behavior which long resisted rigorous mathematical analysis (or even a plausible explanation). We now have a relatively robust mathematical understanding of this fractal nature of the sandpile, which involves surprising connections between integer superharmonic functions on the lattice, discrete tilings of the plane, and Apollonian circle packings. In this talk, we will survey our work in this area, and discuss avenues of current and future research.<br />
<br />
===March 2 Aaron Bertram (Utah)===<br />
<br />
Title: Stability in Algebraic Geometry<br />
<br />
Abstract: Stability was originally introduced in algebraic geometry in the context of finding a projective quotient space for the action of an algebraic group on a projective manifold. This, in turn, led in the 1960s to a notion of slope-stability for vector bundles on a Riemann surface, which was an important tool in the classification of vector bundles. In the 1990s, mirror symmetry considerations led Michael Douglas to notions of stability for "D-branes" (on a higher-dimensional manifold) that corresponded to no previously known mathematical definition. We now understand each of these notions of stability as a distinct point of a complex "stability manifold" that is an important invariant of the (derived) category of complexes of vector bundles of a projective manifold. In this talk I want to give some examples to illustrate the various stabilities, and also to describe some current work in the area.<br />
<br />
===March 16 Anne Gelb (Dartmouth)===<br />
<br />
Title: Reducing the effects of bad data measurements using variance based weighted joint sparsity<br />
<br />
Abstract: We introduce the variance based joint sparsity (VBJS) method for sparse signal recovery and image reconstruction from multiple measurement vectors. Joint sparsity techniques employing $\ell_{2,1}$ minimization are typically used, but the algorithm is computationally intensive and requires fine tuning of parameters. The VBJS method uses a weighted $\ell_1$ joint sparsity algorithm, where the weights depend on the pixel-wise variance. The VBJS method is accurate, robust, cost efficient and also reduces the effects of false data.<br />
<br />
<br />
===April 6 Edray Goins (Purdue)===<br />
<br />
Title: Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups<br />
<br />
Abstract: A Bely&#301; map <math> \beta: \mathbb P^1(\mathbb C) \to \mathbb P^1(\mathbb C) </math> is a rational function with at most three critical values; we may assume these values are <math> \{ 0, \, 1, \, \infty \}. </math> A Dessin d'Enfant is a planar bipartite graph obtained by considering the preimage of a path between two of these critical values, usually taken to be the line segment from 0 to 1. Such graphs can be drawn on the sphere by composing with stereographic projection: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq \mathbb P^1(\mathbb C) \simeq S^2(\mathbb R). </math> Replacing <math> \mathbb P^1 </math> with an elliptic curve <math>E </math>, there is a similar definition of a Bely&#301; map <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C). </math> Since <math> E(\mathbb C) \simeq \mathbb T^2(\mathbb R) </math> is a torus, we call <math> (E, \beta) </math> a toroidal Bely&#301; pair. The corresponding Dessin d'Enfant can be drawn on the torus by composing with an elliptic logarithm: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq E(\mathbb C) \simeq \mathbb T^2(\mathbb R). </math><br />
<br />
This project seeks to create a database of such Bely&#301; pairs, their corresponding Dessins d'Enfant, and their monodromy groups. For each positive integer <math> N </math>, there are only finitely many toroidal Bely&#301; pairs <math> (E, \beta) </math> with <math> \deg \, \beta = N. </math> Using the Hurwitz Genus formula, we can begin this database by considering all possible degree sequences <math> \mathcal D </math> on the ramification indices as multisets on three partitions of N. For each degree sequence, we compute all possible monodromy groups <math> G = \text{im} \, \bigl[ \pi_1 \bigl( \mathbb P^1(\mathbb C) - \{ 0, \, 1, \, \infty \} \bigr) \to S_N \bigr]; </math> they are the ``Galois closure'' of the group of automorphisms of the graph. Finally, for each possible monodromy group, we compute explicit formulas for Bely&#301; maps <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C) </math> associated to some elliptic curve <math> E: \ y^2 = x^3 + A \, x + B. </math> We will discuss some of the challenges of determining the structure of these groups, and present visualizations of group actions on the torus. <br />
<br />
This work is part of PRiME (Purdue Research in Mathematics Experience) with Chineze Christopher, Robert Dicks, Gina Ferolito, Joseph Sauder, and Danika Van Niel with assistance by Edray Goins and Abhishek Parab.<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank Colloquia]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall18&diff=15275Colloquia/Fall182018-03-19T17:20:59Z<p>Craciun: </p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
== Spring 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|January 29 (Monday)<br />
| [http://www.math.columbia.edu/~chaoli/ Li Chao] (Columbia)<br />
|[[#January 29 Li Chao (Columbia)| Elliptic curves and Goldfeld's conjecture ]]<br />
| Jordan Ellenberg<br />
|<br />
|-<br />
|February 2 (Room: 911)<br />
| [https://scholar.harvard.edu/tfai/home Thomas Fai] (Harvard)<br />
|[[#February 2 Thomas Fai (Harvard)| The Lubricated Immersed Boundary Method ]]<br />
| Spagnolie, Smith<br />
|<br />
|-<br />
|February 5 (Monday, Room: 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 5 Alex Lubotzky (Hebrew University)| High dimensional expanders: From Ramanujan graphs to Ramanujan complexes ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 6 (Tuesday 2 pm, Room 911)<br />
| [http://www.ma.huji.ac.il/~alexlub/ Alex Lubotzky] (Hebrew University) <br />
|[[#February 6 Alex Lubotzky (Hebrew University)| Groups' approximation, stability and high dimensional expanders ]]<br />
| Ellenberg, Gurevitch<br />
|<br />
|-<br />
|February 9<br />
| [http://www.math.cmu.edu/~wes/ Wes Pegden] (CMU)<br />
|[[#February 9 Wes Pegden (CMU)| The fractal nature of the Abelian Sandpile ]]<br />
| Roch<br />
|<br />
|-<br />
|March 2<br />
| [http://www.math.utah.edu/~bertram/ Aaron Bertram] (University of Utah)<br />
|[[#March 2 Aaron Bertram (Utah)| Stability in Algebraic Geometry ]]<br />
| Caldararu<br />
|<br />
|-<br />
| March 16 (Room: 911)<br />
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)<br />
|[[#March 16 Anne Gelb (Dartmouth)| Reducing the effects of bad data measurements using variance based weighted joint sparsity ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 5 (Thursday)<br />
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)<br />
|[[# TBA| TBA ]]<br />
| Craciun<br />
|<br />
|-<br />
| April 6<br />
| [https://www.math.purdue.edu/~egoins Edray Goins] (Purdue)<br />
|[[# Edray Goins| Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups ]]<br />
| Melanie<br />
|<br />
|-<br />
| April 13<br />
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 16 (Monday)<br />
| [http://www-users.math.umn.edu/~cberkesc/ Christine Berkesch Zamaere ] (University of Minnesota)<br />
|[[# TBA| TBA ]]<br />
| Erman, Sam<br />
|<br />
|-<br />
| April 25 (Wednesday)<br />
| [http://www.f.waseda.jp/hitoshi.ishii/ Hitoshi Ishii] (Waseda University) Wasow lecture<br />
|[[# TBA| TBA ]]<br />
| Tran<br />
|<br />
|-<br />
| May 4<br />
| [http://math.mit.edu/~cohn/ Henry Cohn] (Microsoft Research and MIT)<br />
|[[# TBA| TBA ]]<br />
| Ellenberg<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|}<br />
<br />
== Spring Abstracts ==<br />
<br />
<br />
===January 29 Li Chao (Columbia)===<br />
<br />
Title: Elliptic curves and Goldfeld's conjecture<br />
<br />
Abstract: <br />
An elliptic curve is a plane curve defined by a cubic equation. Determining whether such an equation has infinitely many rational solutions has been a central problem in number theory for centuries, which lead to the celebrated conjecture of Birch and Swinnerton-Dyer. Within a family of elliptic curves (such as the Mordell curve family y^2=x^3-d), a conjecture of Goldfeld further predicts that there should be infinitely many rational solutions exactly half of the time. We will start with a history of this problem, discuss our recent work (with D. Kriz) towards Goldfeld's conjecture and illustrate the key ideas and ingredients behind these new progresses.<br />
<br />
=== February 2 Thomas Fai (Harvard) ===<br />
<br />
Title: The Lubricated Immersed Boundary Method<br />
<br />
Abstract:<br />
Many real-world examples of fluid-structure interaction, including the transit of red blood cells through the narrow slits in the spleen, involve the near-contact of elastic structures separated by thin layers of fluid. The separation of length scales between these fine lubrication layers and the larger elastic objects poses significant computational challenges. Motivated by the challenge of resolving such multiscale problems, we introduce an immersed boundary method that uses elements of lubrication theory to resolve thin fluid layers between immersed boundaries. We apply this method to two-dimensional flows of increasing complexity, including eccentric rotating cylinders and elastic vesicles near walls in shear flow, to show its increased accuracy compared to the classical immersed boundary method. We present preliminary simulation results of cell suspensions, a problem in which near-contact occurs at multiple levels, such as cell-wall, cell-cell, and intracellular interactions, to highlight the importance of resolving thin fluid layers in order to obtain the correct overall dynamics.<br />
<br />
===February 5 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: High dimensional expanders: From Ramanujan graphs to Ramanujan complexes<br />
<br />
Abstract: <br />
<br />
Expander graphs in general, and Ramanujan graphs , in particular, have played a major role in computer science in the last 5 decades and more recently also in pure math. The first explicit construction of bounded degree expanding graphs was given by Margulis in the early 70's. In mid 80' Margulis and Lubotzky-Phillips-Sarnak provided Ramanujan graphs which are optimal such expanders. <br />
<br />
In recent years a high dimensional theory of expanders is emerging. A notion of topological expanders was defined by Gromov in 2010 who proved that the complete d-dimensional simplical complexes are such. He raised the basic question of existence of such bounded degree complexes of dimension d>1. <br />
<br />
This question was answered recently affirmatively (by T. Kaufman, D. Kazdhan and A. Lubotzky for d=2 and by S. Evra and T. Kaufman for general d) by showing that the d-skeleton of (d+1)-dimensional Ramanujan complexes provide such topological expanders. We will describe these developments and the general area of high dimensional expanders. <br />
<br />
<br />
===February 6 Alex Lubotzky (Hebrew University)===<br />
<br />
Title: Groups' approximation, stability and high dimensional expanders<br />
<br />
Abstract: <br />
<br />
Several well-known open questions, such as: are all groups sofic or hyperlinear?, have a common form: can all groups be approximated by asymptotic homomorphisms into the symmetric groups Sym(n) (in the sofic case) or the unitary groups U(n) (in the hyperlinear case)? In the case of U(n), the question can be asked with respect to different metrics and norms. We answer, for the first time, one of these versions, showing that there exist fintely presented groups which are not approximated by U(n) with respect to the Frobenius (=L_2) norm.<br />
<br />
The strategy is via the notion of "stability": some higher dimensional cohomology vanishing phenomena is proven to imply stability and using high dimensional expanders, it is shown that some non-residually finite groups (central extensions of some lattices in p-adic Lie groups) are Frobenious stable and hence cannot be Frobenius approximated. <br />
<br />
All notions will be explained. Joint work with M, De Chiffre, L. Glebsky and A. Thom.<br />
<br />
===February 9 Wes Pegden (CMU)===<br />
<br />
Title: The fractal nature of the Abelian Sandpile <br />
<br />
Abstract: The Abelian Sandpile is a simple diffusion process on the integer lattice, in which configurations of chips disperse according to a simple rule: when a vertex has at least 4 chips, it can distribute one chip to each neighbor. <br />
<br />
Introduced in the statistical physics community in the 1980s, the Abelian sandpile exhibits striking fractal behavior which long resisted rigorous mathematical analysis (or even a plausible explanation). We now have a relatively robust mathematical understanding of this fractal nature of the sandpile, which involves surprising connections between integer superharmonic functions on the lattice, discrete tilings of the plane, and Apollonian circle packings. In this talk, we will survey our work in this area, and discuss avenues of current and future research.<br />
<br />
===March 2 Aaron Bertram (Utah)===<br />
<br />
Title: Stability in Algebraic Geometry<br />
<br />
Abstract: Stability was originally introduced in algebraic geometry in the context of finding a projective quotient space for the action of an algebraic group on a projective manifold. This, in turn, led in the 1960s to a notion of slope-stability for vector bundles on a Riemann surface, which was an important tool in the classification of vector bundles. In the 1990s, mirror symmetry considerations led Michael Douglas to notions of stability for "D-branes" (on a higher-dimensional manifold) that corresponded to no previously known mathematical definition. We now understand each of these notions of stability as a distinct point of a complex "stability manifold" that is an important invariant of the (derived) category of complexes of vector bundles of a projective manifold. In this talk I want to give some examples to illustrate the various stabilities, and also to describe some current work in the area.<br />
<br />
===March 16 Anne Gelb (Dartmouth)===<br />
<br />
Title: Reducing the effects of bad data measurements using variance based weighted joint sparsity<br />
<br />
Abstract: We introduce the variance based joint sparsity (VBJS) method for sparse signal recovery and image reconstruction from multiple measurement vectors. Joint sparsity techniques employing $\ell_{2,1}$ minimization are typically used, but the algorithm is computationally intensive and requires fine tuning of parameters. The VBJS method uses a weighted $\ell_1$ joint sparsity algorithm, where the weights depend on the pixel-wise variance. The VBJS method is accurate, robust, cost efficient and also reduces the effects of false data.<br />
<br />
<br />
===April 6 Edray Goins (Purdue)===<br />
<br />
Title: Toroidal Bely&#301; Pairs, Toroidal Graphs, and their Monodromy Groups<br />
<br />
Abstract: A Bely&#301; map <math> \beta: \mathbb P^1(\mathbb C) \to \mathbb P^1(\mathbb C) </math> is a rational function with at most three critical values; we may assume these values are <math> \{ 0, \, 1, \, \infty \}. </math> A Dessin d'Enfant is a planar bipartite graph obtained by considering the preimage of a path between two of these critical values, usually taken to be the line segment from 0 to 1. Such graphs can be drawn on the sphere by composing with stereographic projection: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq \mathbb P^1(\mathbb C) \simeq S^2(\mathbb R). </math> Replacing <math> \mathbb P^1 </math> with an elliptic curve <math>E </math>, there is a similar definition of a Bely&#301; map <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C). </math> Since <math> E(\mathbb C) \simeq \mathbb T^2(\mathbb R) </math> is a torus, we call <math> (E, \beta) </math> a toroidal Bely&#301; pair. The corresponding Dessin d'Enfant can be drawn on the torus by composing with an elliptic logarithm: <math> \beta^{-1} \bigl( [0,1] \bigr) \subseteq E(\mathbb C) \simeq \mathbb T^2(\mathbb R). </math><br />
<br />
This project seeks to create a database of such Bely&#301; pairs, their corresponding Dessins d'Enfant, and their monodromy groups. For each positive integer <math> N </math>, there are only finitely many toroidal Bely&#301; pairs <math> (E, \beta) </math> with <math> \deg \, \beta = N. </math> Using the Hurwitz Genus formula, we can begin this database by considering all possible degree sequences <math> \mathcal D </math> on the ramification indices as multisets on three partitions of N. For each degree sequence, we compute all possible monodromy groups <math> G = \text{im} \, \bigl[ \pi_1 \bigl( \mathbb P^1(\mathbb C) - \{ 0, \, 1, \, \infty \} \bigr) \to S_N \bigr]; </math> they are the ``Galois closure'' of the group of automorphisms of the graph. Finally, for each possible monodromy group, we compute explicit formulas for Bely&#301; maps <math> \beta: E(\mathbb C) \to \mathbb P^1(\mathbb C) </math> associated to some elliptic curve <math> E: \ y^2 = x^3 + A \, x + B. </math> We will discuss some of the challenges of determining the structure of these groups, and present visualizations of group actions on the torus. <br />
<br />
This work is part of PRiME (Purdue Research in Mathematics Experience) with Chineze Christopher, Robert Dicks, Gina Ferolito, Joseph Sauder, and Danika Van Niel with assistance by Edray Goins and Abhishek Parab.<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank Colloquia]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF17&diff=14616Applied/ACMS/absF172017-11-29T20:22:02Z<p>Craciun: /* Minh Binh Tran (UW) */</p>
<hr />
<div>= ACMS Abstracts: Fall 2017 =<br />
<br />
=== Jinzi Mac Huang (Courant) ===<br />
<br />
''Sculpting of a dissolving body''<br />
<br />
In geology, dissolution in fluids leads to natural pattern formations. For example the Karst topography occurs when water dissolves limestone, and travertine terraces form as a balance of dissolution and precipitation. In this talk, we consider the shape dynamics of a soluble object immersed in water, with either external flow imposed or convective flow under gravity. We find that different flow configurations lead to different shape dynamics, for example a terminal self-similar shape emerges from dissolving in external flow, while fine scale patterns form when no external flow is imposed. We also find that under gravity, a dissolving body with initially smooth surface evolves into an increasingly sharp needle shape. A mathematical model predicts that a geometric shock forms at the tip of dissolved body, with the tip curvature becoming infinite in finite time.<br />
<br />
=== Dongnam Ko (Seoul National Univ.) ===<br />
<br />
''On the emergence of local flocking phenomena in Cucker-Smale ensembles''<br />
<br />
Emergence of flocking groups are often observed in many complex network systems. The Cucker-Smale model is one of the flocking model, which describes the dynamics of attracting particles. This talk concerns time-asymptotic behaviors of Cucker-Smale particle ensembles, especially for mono-cluster and bi-cluster flockings. The emergence of flocking phenomena is determined by sufficient initial conditions, coupling strength, and communication weight decay. Our asymptotic analysis uses the Lyapunov functional approach and a Lagrangian formulation of the coupled system. We derive a system of differential inequalities for the functionals that measure the local fluctuations and group separations along particle trajectories. The bootstrapping argument is the key idea to prove the gathering and separating behaviors of Cucker-Smale particles simultaneously.<br />
<br />
=== Yingwei Wang (UW-Madison) ===<br />
<br />
''Introduction to Muntz Polynomial Approximation''<br />
<br />
In general, solutions to the Laplacian equation enjoy relatively high smoothness. However, they can exhibit singular behaviors at domain corners or points where boundary conditions change type. In this talk, I will focus on the mixed Dirichlet-Neumann boundary conditions for Laplacian equation, and discuss how singularities in this case adversely affect the accuracy and convergence rates of standard numerical methods. Then, starting from the celebrated Weierstrass theorem about polynomial approximation, I will describe the approximation theory related to the so-called Muntz polynomials, which can be viewed as a generalization of usual polynomials. Additionally, I will illustrate the idea of Muntz-Galerkin methods, and show that how they can overcome the difficulties to achieving high order accuracy for the problems with singularities.<br />
<br />
=== Jianlin Xia (Purdue Univ.) ===<br />
<br />
''Fast Randomized Direct Solvers for Large Linear Systems''<br />
<br />
In this talk, we discuss how randomized techniques can be used in structured matrix compression, and in turn in solving large dense and sparse linear systems. It is known that randomized sampling can help compute approximate SVDs via matrix-vector products. Such randomized ideas have been applied to some structured matrices for the fast compression of off-diagonal blocks. This leads to randomized and even matrix-free direct solvers for large dense linear systems.<br />
<br />
Furthermore, the techniques can be extended to sparse direct solvers, where randomization helps compress dense fill-in in the factorization into skinny matrix-vector products. This has a significant advantage over dense or structured fill-in used before, since the processing and propagation of the skinny products are much simpler. For some sparse discretized problems (often elliptic), the randomized sparse direct solvers can reach nearly O(n) complexity.<br />
<br />
We also show how to control the approximation accuracy in randomized structured solution, and further prove the superior backward stability of these randomized methods. Part of the work is joint with Yuanzhe Xi.<br />
<br />
=== Yuri Lvov (Rensselaer Polytechnic Institute) ===<br />
<br />
''Fermi Pasta Ulam Tsingou (FPUT) chain - new ideas about old problem''<br />
<br />
Fermi-Pasta-Ulam-Tsingou chain is a theoretical model of a one<br />
dimensional crystal. It consists of point masses connected by<br />
nonlinear strings. Enrico Fermi, John Pasta, Stanislaw Ulam, and Mary<br />
Tsingou conducted numerical experiments on this model in 1953, and<br />
found that, contrary to their expectations, the system would not reach<br />
thermodynamic equilibrium.<br />
<br />
We study FPUT problem by applying the wave turbulence theory. We find<br />
that the resonant interactions of SIX waves does lead to irreversible<br />
energy mixing and eventually to the thermalization of the energy in<br />
the spectrum. We consider FPUT with quadratic (alpha FPUT model)<br />
and qubic (beta FPUT model) nonlinearities. We predict that for the<br />
alpha FPUT model the time scale to reach thermal equilibrium is of<br />
the order of 1/alpha^8. For the beta FPUT model the time to<br />
reach equipartitiion is of the order of 1/beta^4. This is why the<br />
emergence of equipartition requires such a long time, inaccessible in<br />
the fifties.<br />
<br />
These results were obtained in collaboration with Miguel Onorato, Lara<br />
Vozella and Davide Proment<br />
<br />
=== Becca Thomases (UC Davis) ===<br />
<br />
''Microorganism locomotion in viscoelastic fluids''<br />
<br />
Many important biological functions depend on microorganisms' ability to move in viscoelastic fluids such as mucus and wet soil. The effects of fluid elasticity on motility remain poorly understood, partly because, the swimmer strokes depend on the properties of the fluid medium, which obfuscates the mechanisms responsible for observed behavioral changes. In this study, we use experimental data on the gaits of the algal cell C. reinhardtii swimming in Newtonian and viscoelastic fluids as inputs to numerical simulations that decouple the swimmer gait and fluid type in order to isolate the effect of fluid elasticity on swimming. In viscoelastic fluids, cells employing the Newtonian gait swim faster but generate larger stresses and use more power, and as a result the viscoelastic gait is more efficient. Furthermore, we show that fundamental principles of swimming based on viscous fluid theory miss important flow dynamics: fluid elasticity provides an elastic memory effect which increases both the forward and backward speeds, and (unlike purely viscous fluids) larger fluid stress accumulates around flagella moving tangent to the swimming direction, compared to the normal direction.<br />
<br />
=== Charles Doering (U. Michigan) ===<br />
<br />
''Optimal bounds and extremal trajectories for time averages in nonlinear dynamical systems''<br />
<br />
For quantities of interest in a dynamical system governed by differential equations it is natural to seek the largest (or smallest) long-time average among solution trajectories. Upper bounds can be proved a priori using auxiliary functions, the optimal choice of which is a convex optimization. The problems of finding maximal trajectories and minimal auxiliary functions are in fact strongly dual so auxiliary functions can produce arbitrarily sharp upper bounds on maximal time averages. They also define volumes in phase space where maximal trajectories must lie. For polynomial equations of motion auxiliary functions can be constructed by semidefinite programming, which we illustrate using the Lorenz and Kuramoto Sivashinsy equations. This is joint work with Ian Tobasco and David Goluskin.<br />
<br />
=== Minh Binh Tran (UW) ===<br />
<br />
''Some recent progress on wave turbulence and quantum kinetics''<br />
<br />
Wave turbulence is a branch of science studying the out-of-equilibrium statistical mechanics of random nonlinear waves of all kinds and scales. Despite the fact that wave fields in nature are enormously diverse, there is a common mathematical concept that can be used to describe the processes of random wave interactions: the wave kinetic equations. After the production of the first Bose-Einstein Condensates (BECs), there has been an explosion of physics research on the kinetic theory associated to BECs and their thermal clouds. In this talk, we will summarize our recent progress on this topic.</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=14612Applied/ACMS2017-11-29T19:22:40Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
== Fall 2017 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept. 8<br />
|[http://math.nyu.edu/~jinzi/ Jinzi Mac Huang] (Courant)<br />
|''[[Applied/ACMS/absF17#Jinzi Mac Huang (Courant)|Sculpting of a dissolving body]]''<br />
| Spagnolie<br />
|-<br />
| Sept. 29<br />
|[https://dongnamko.wordpress.com/ Dongnam Ko] (Seoul National Univ.)<br />
|''[[Applied/ACMS/absF17#Dongnam Ko (Seoul National Univ.)|On the emergence of local flocking phenomena in Cucker-Smale ensembles]]''<br />
|Jin<br />
|-<br />
| Oct. 13<br />
|[http://www.math.wisc.edu/~ywang/ Yingwei Wang] (UW)<br />
|''[[Applied/ACMS/absF17#Yingwei Wang (UW)|Introduction to Muntz Polynomial Approximation]]''<br />
|Spagnolie<br />
|-<br />
| Oct. 20<br />
|[https://www.math.purdue.edu/~xiaj/ Jianlin Xia] (Purdue)<br />
|''[[Applied/ACMS/absF17#Jianlin Xia (Purdue)|Fast Randomized Direct Solvers for Large Linear Systems]]''<br />
|Li<br />
|-<br />
| Oct. 27<br />
|[https://www.rpi.edu/dept/math/ms_faculty/profile/lvov_y.html Yuri Lvov] (Rensselaer Polytechnic Institute)<br />
|''[[Applied/ACMS/absF17#Yuri Lvov (Rensselaer Polytechnic Institute)|Fermi Pasta Ulam Tsingou (FPUT) chain - new ideas about old problem]]''<br />
|Smith<br />
|-<br />
| Nov. 3<br />
|[https://www.math.ucdavis.edu/~thomases/ Becca Thomases] (UC Davis)<br />
|''[[Applied/ACMS/absF17#Becca Thomases (UC Davis)|Microorganism locomotion in viscoelastic fluids]]''<br />
| Spagnolie<br />
|-<br />
| Nov. 17<br />
|[https://scholar.google.com/citations?user=HXLAUSIAAAAJ&hl=en Charles Doering] (Michigan)<br />
|''[[Applied/ACMS/absF17#Charles Doering (Michigan)|Optimal bounds and extremal trajectories for time averages in nonlinear dynamical systems]]''<br />
| Spagnolie, Thiffeault<br />
|-<br />
| Nov. 25<br />
| Thanksgiving recess<br />
|<br />
|<br />
|-<br />
| Dec. 1<br />
|[http://minhbinhtran.org/ Minh Binh Tran] (UW)<br />
|''[[Applied/ACMS/absF17#Minh Binh Tran (UW)|Some recent progress on wave turbulence and quantum kinetics]]''<br />
| Spagnolie, Thiffeault<br />
|-<br />
| Dec. 8<br />
|[https://www.math.utah.edu/~fogelson/ Aaron Fogelson] (Utah)<br />
|''[[Applied/ACMS/absF17#Aaron Fogelson (Utah)|TBA]]''<br />
| Spagnolie<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall18&diff=14410Colloquia/Fall182017-10-20T20:30:16Z<p>Craciun: /* Spring 2018 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<!-- ==[[Tentative Colloquia|Tentative schedule for next semester]] == --><br />
<br />
==Fall 2017==<br />
<br />
{| cellpadding="8"<br />
!align="left" | Date <br />
!align="left" | Speaker<br />
!align="left" | Title<br />
!align="left" | Host(s)<br />
|-<br />
|September 8<br />
| [https://sites.google.com/a/wisc.edu/theresa-c-anderson/home/ Tess Anderson] (Madison)<br />
|[[#September 8: Tess Anderson (Madison) | A Spherical Maximal Function along the Primes ]]<br />
| Yang<br />
|<br />
|-<br />
|September 15<br />
|<br />
|[[#| ]]<br />
|<br />
|<br />
|<br />
|-<br />
|September 22, '''9th floor'''<br />
| Jaeyoung Byeon (KAIST)<br />
|[[#September 22: Jaeyoung Byeon (KAIST) | Patterns formation for elliptic systems with large interaction forces ]]<br />
| Rabinowitz & Kim<br />
|<br />
|-<br />
|September 29<br />
|<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|October 6, '''9th floor'''<br />
| [http://www3.nd.edu/~jhauenst/ Jonathan Hauenstein] (Notre Dame)<br />
|[[#October 6: Jonathan Hauenstein (Notre Dame) | Real solutions of polynomial equations ]]<br />
| Boston<br />
| <br />
|-<br />
|October 13, '''9th floor'''<br />
| [http://www.tomokokitagawa.com/ Tomoko L. Kitagawa] (Berkeley)<br />
|[[#October 13: Tomoko Kitagawa (Berkeley) | A Global History of Mathematics from 1650 to 2017 ]]<br />
| Max<br />
|<br />
|-<br />
|October 20<br />
| [http://cims.nyu.edu/~pgermain/ Pierre Germain] (Courant, NYU) <br />
|[[#October 13: Pierre Germain (Courant, NYU) | Stability of the Couette flow in the Euler and Navier-Stokes equations ]]<br />
| Minh-Binh Tran<br />
|<br />
|-<br />
|October 27<br />
|Stefanie Petermichl (Toulouse)<br />
|[[# TBA| TBA ]]<br />
| Stovall, Seeger<br />
|<br />
|-<br />
|We, November 1<br />
|Shaoming Guo (Indiana)<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 3<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 10<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 17<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 24<br />
|'''Thanksgiving break'''<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|December 1<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|December 8<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
<br />
|}<br />
<br />
== Fall Abstracts ==<br />
=== September 8: Tess Anderson (Madison) ===<br />
Title: A Spherical Maximal Function along the Primes<br />
<br />
Abstract: Many problems at the interface of analysis and number theory involve showing that the primes, though deterministic, exhibit random behavior. The Green-Tao theorem stating that the primes contain infinitely long arithmetic progressions is one such example. In this talk, we show that prime vectors equidistribute on the sphere in the same manner as a random set of integer vectors would be expected to. We further quantify this with explicit bounds for naturally occurring maximal functions, which connects classical tools from harmonic analysis with analytic number theory. This is joint work with Cook, Hughes, and Kumchev.<br />
<br />
<br />
=== September 22: Jaeyoung Byeon (KAIST) ===<br />
Title: Patterns formation for elliptic systems with large interaction forces<br />
<br />
Abstract: Nonlinear elliptic systems arising from nonlinear Schroedinger systems have simple looking reaction terms. The corresponding energy for the reaction terms can be expressed as quadratic forms in terms of density functions. The i, j-th entry of the matrix for the quadratic form represents the interaction force between the components i and j of the system. If the sign of an entry is positive, the force between the two components is attractive; on the other hand, if it is negative, it is repulsive. When the interaction forces between different components are large, the network structure of attraction and repulsion between components might produce several interesting patterns for solutions. As a starting point to study the general pattern formation structure for systems with a large number of components, I will first discuss the simple case of 2-component systems, and then the much more complex case of 3-component systems.<br />
<br />
===October 6: Jonathan Hauenstein (Notre Dame) ===<br />
Title: Real solutions of polynomial equations<br />
<br />
Abstract: Systems of nonlinear polynomial equations arise frequently in applications with the set of real solutions typically corresponding to physically meaningful solutions. Efficient algorithms for computing real solutions are designed by exploiting structure arising from the application. This talk will highlight some of these algorithms for various applications such as solving steady-state problems of hyperbolic conservation laws, solving semidefinite programs, and computing all steady-state solutions of the Kuramoto model.<br />
<br />
===October 13: Tomoko Kitagawa (Berkeley) ===<br />
Title: A Global History of Mathematics from 1650 to 2017<br />
<br />
Abstract: This is a talk on the global history of mathematics. We will first focus on France by revisiting some of the conversations between Blaise Pascal (1623–1662) and Pierre de Fermat (1607–1665). These two “mathematicians” discussed ways of calculating the possibility of winning a gamble and exchanged their opinions on geometry. However, what about the rest of the world? We will embark on a long oceanic voyage to get to East Asia and uncover the unexpected consequences of blending foreign mathematical knowledge into domestic intelligence, which was occurring concurrently in Beijing and Kyoto. How did mathematicians and scientists contribute to the expansion of knowledge? What lessons do we learn from their experiences?<br />
<br />
===October 13: Pierre Germain (Courant, NYU) ===<br />
Title: Stability of the Couette flow in the Euler and Navier-Stokes equations<br />
<br />
Abstract: I will discuss the question of the (asymptotic) stability of the Couette flow in Euler and Navier-Stokes. The Couette flow is the simplest nontrivial stationary flow, and the first one for which this question can be fully answered. The answer involves the mathematical understanding of important physical phenomena such as inviscid damping and enhanced dissipation. I will present recent results in dimension 2 (Bedrossian-Masmoudi) and dimension 3 (Bedrossian-Germain-Masmoudi).<br />
<br />
== Spring 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| March 16<br />
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 4 (Wednesday)<br />
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)<br />
|[[# TBA| TBA ]]<br />
| Craciun<br />
|<br />
|-<br />
| April 6<br />
| Reserved<br />
|[[# TBA| TBA ]]<br />
| Melanie<br />
|<br />
|-<br />
| April 13<br />
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
| hosting faculty<br />
|<br />
|}<br />
<br />
== Spring Abstracts ==<br />
<br />
=== <DATE>: <PERSON> (INSTITUTION) ===<br />
Title: <TITLE><br />
<br />
Abstract: <ABSTRACT><br />
<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank Colloquia]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall18&diff=14409Colloquia/Fall182017-10-20T20:24:34Z<p>Craciun: /* Spring 2018 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<!-- ==[[Tentative Colloquia|Tentative schedule for next semester]] == --><br />
<br />
==Fall 2017==<br />
<br />
{| cellpadding="8"<br />
!align="left" | Date <br />
!align="left" | Speaker<br />
!align="left" | Title<br />
!align="left" | Host(s)<br />
|-<br />
|September 8<br />
| [https://sites.google.com/a/wisc.edu/theresa-c-anderson/home/ Tess Anderson] (Madison)<br />
|[[#September 8: Tess Anderson (Madison) | A Spherical Maximal Function along the Primes ]]<br />
| Yang<br />
|<br />
|-<br />
|September 15<br />
|<br />
|[[#| ]]<br />
|<br />
|<br />
|<br />
|-<br />
|September 22, '''9th floor'''<br />
| Jaeyoung Byeon (KAIST)<br />
|[[#September 22: Jaeyoung Byeon (KAIST) | Patterns formation for elliptic systems with large interaction forces ]]<br />
| Rabinowitz & Kim<br />
|<br />
|-<br />
|September 29<br />
|<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|October 6, '''9th floor'''<br />
| [http://www3.nd.edu/~jhauenst/ Jonathan Hauenstein] (Notre Dame)<br />
|[[#October 6: Jonathan Hauenstein (Notre Dame) | Real solutions of polynomial equations ]]<br />
| Boston<br />
| <br />
|-<br />
|October 13, '''9th floor'''<br />
| [http://www.tomokokitagawa.com/ Tomoko L. Kitagawa] (Berkeley)<br />
|[[#October 13: Tomoko Kitagawa (Berkeley) | A Global History of Mathematics from 1650 to 2017 ]]<br />
| Max<br />
|<br />
|-<br />
|October 20<br />
| [http://cims.nyu.edu/~pgermain/ Pierre Germain] (Courant, NYU) <br />
|[[#October 13: Pierre Germain (Courant, NYU) | Stability of the Couette flow in the Euler and Navier-Stokes equations ]]<br />
| Minh-Binh Tran<br />
|<br />
|-<br />
|October 27<br />
|Stefanie Petermichl (Toulouse)<br />
|[[# TBA| TBA ]]<br />
| Stovall, Seeger<br />
|<br />
|-<br />
|We, November 1<br />
|Shaoming Guo (Indiana)<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 3<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 10<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 17<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|November 24<br />
|'''Thanksgiving break'''<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|December 1<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
|December 8<br />
| Reserved for possible job talks<br />
|[[# TBA| TBA ]]<br />
|<br />
|<br />
|-<br />
<br />
|}<br />
<br />
== Fall Abstracts ==<br />
=== September 8: Tess Anderson (Madison) ===<br />
Title: A Spherical Maximal Function along the Primes<br />
<br />
Abstract: Many problems at the interface of analysis and number theory involve showing that the primes, though deterministic, exhibit random behavior. The Green-Tao theorem stating that the primes contain infinitely long arithmetic progressions is one such example. In this talk, we show that prime vectors equidistribute on the sphere in the same manner as a random set of integer vectors would be expected to. We further quantify this with explicit bounds for naturally occurring maximal functions, which connects classical tools from harmonic analysis with analytic number theory. This is joint work with Cook, Hughes, and Kumchev.<br />
<br />
<br />
=== September 22: Jaeyoung Byeon (KAIST) ===<br />
Title: Patterns formation for elliptic systems with large interaction forces<br />
<br />
Abstract: Nonlinear elliptic systems arising from nonlinear Schroedinger systems have simple looking reaction terms. The corresponding energy for the reaction terms can be expressed as quadratic forms in terms of density functions. The i, j-th entry of the matrix for the quadratic form represents the interaction force between the components i and j of the system. If the sign of an entry is positive, the force between the two components is attractive; on the other hand, if it is negative, it is repulsive. When the interaction forces between different components are large, the network structure of attraction and repulsion between components might produce several interesting patterns for solutions. As a starting point to study the general pattern formation structure for systems with a large number of components, I will first discuss the simple case of 2-component systems, and then the much more complex case of 3-component systems.<br />
<br />
===October 6: Jonathan Hauenstein (Notre Dame) ===<br />
Title: Real solutions of polynomial equations<br />
<br />
Abstract: Systems of nonlinear polynomial equations arise frequently in applications with the set of real solutions typically corresponding to physically meaningful solutions. Efficient algorithms for computing real solutions are designed by exploiting structure arising from the application. This talk will highlight some of these algorithms for various applications such as solving steady-state problems of hyperbolic conservation laws, solving semidefinite programs, and computing all steady-state solutions of the Kuramoto model.<br />
<br />
===October 13: Tomoko Kitagawa (Berkeley) ===<br />
Title: A Global History of Mathematics from 1650 to 2017<br />
<br />
Abstract: This is a talk on the global history of mathematics. We will first focus on France by revisiting some of the conversations between Blaise Pascal (1623–1662) and Pierre de Fermat (1607–1665). These two “mathematicians” discussed ways of calculating the possibility of winning a gamble and exchanged their opinions on geometry. However, what about the rest of the world? We will embark on a long oceanic voyage to get to East Asia and uncover the unexpected consequences of blending foreign mathematical knowledge into domestic intelligence, which was occurring concurrently in Beijing and Kyoto. How did mathematicians and scientists contribute to the expansion of knowledge? What lessons do we learn from their experiences?<br />
<br />
===October 13: Pierre Germain (Courant, NYU) ===<br />
Title: Stability of the Couette flow in the Euler and Navier-Stokes equations<br />
<br />
Abstract: I will discuss the question of the (asymptotic) stability of the Couette flow in Euler and Navier-Stokes. The Couette flow is the simplest nontrivial stationary flow, and the first one for which this question can be fully answered. The answer involves the mathematical understanding of important physical phenomena such as inviscid damping and enhanced dissipation. I will present recent results in dimension 2 (Bedrossian-Masmoudi) and dimension 3 (Bedrossian-Germain-Masmoudi).<br />
<br />
== Spring 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| March 16<br />
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
| April 6<br />
| Reserved<br />
|[[# TBA| TBA ]]<br />
| Melanie<br />
|<br />
|-<br />
| April 13<br />
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)<br />
|[[# TBA| TBA ]]<br />
| WIMAW<br />
|<br />
|-<br />
|April 2<br />
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)<br />
|[[# TBA| TBA ]]<br />
| Craciun<br />
|<br />
|-<br />
|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
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|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
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|-<br />
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|[[# TBA| TBA ]]<br />
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|[[# TBA| TBA ]]<br />
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| person (institution)<br />
|[[# TBA| TBA ]]<br />
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|date<br />
| person (institution)<br />
|[[# TBA| TBA ]]<br />
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|[[# TBA| TBA ]]<br />
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|[[# TBA| TBA ]]<br />
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|[[# TBA| TBA ]]<br />
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|[[# TBA| TBA ]]<br />
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|<br />
|}<br />
<br />
== Spring Abstracts ==<br />
<br />
=== <DATE>: <PERSON> (INSTITUTION) ===<br />
Title: <TITLE><br />
<br />
Abstract: <ABSTRACT><br />
<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank Colloquia]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=11835Applied/ACMS2016-04-18T21:13:46Z<p>Craciun: /* Spring 2016 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2016 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 22<br />
| [https://sites.google.com/a/eng.ucsd.edu/sgls/ Stefan Llewellyn Smith] (UCSD)<br />
| [[Applied/ACMS/absS16#Stefan Llewellyn-Smith (UCSD)| Hollow vortices]] <br />
| Saverio<br />
|-<br />
| Jan 29<br />
| [http://www.eg.bucknell.edu/physics/solomon.html Tom Solomon] (Bucknell)<br />
| [[Applied/ACMS/absS16#Tom Solomon (Bucknell)| Experimental studies of reaction front barriers in laminar flows ]]<br />
| Jean-Luc and Marko<br />
|-<br />
| Feb 5 <br />
| [http://www.math.ku.dk/~d.cappelletti/ Daniele Cappelletti] (KU) <br />
| [[Applied/ACMS/absS16#Daniele Cappelletti (KU)| Deterministic and stochastic reaction networks ]]<br />
| Craciun<br />
|-<br />
| Feb 12 <br />
| Lihui Chai (UCSB)<br />
| [[Applied/ACMS/absS16#Lihui Chai (UCSB)| Semiclassical limit of the Schrödinger-Poisson-Landau-Lifshitz-Gilbert system ]]<br />
| Qin<br />
|-<br />
| '''Feb 12, 4pm, B239'''<br />
|[http://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU) <br />
| [[Colloquia#February 12: Gautam Iyer (CMU)| Homogenization and Anomalous Diffusion]]<br />
| Jean-Luc<br />
|-<br />
| Feb 19 <br />
| [http://directory.engr.wisc.edu/me/Faculty/Roldan-alzate_Alejandro/ Alejandro Roldán-Alzate] (UW) <br />
| [[Applied/ACMS/absS16#Alejandro Roldan-Alzate (UW)| Non–invasive patient-specific cardiovascular fluid dynamics]]<br />
| Saverio<br />
|-<br />
| Feb 26 <br />
| [http://math.sjtu.edu.cn/Showteacher.aspx?id=19&info_lb=98 Yachun Li] (SJTU)<br />
| [[Applied/ACMS/absS16#Yachun Li (SJTU)| Vanishing viscosity limit of the compressible Isentropic Navier-Stokes equations with degenerate viscosities]] <br />
| Shi Jin<br />
|-<br />
| ''' Mar 4, 4pm, B239'''<br />
|[http://www.columbia.edu/~gb2030/ Guillaume Bal] (Columbia University)<br />
|[[Colloquia#September 11: Guillaume Bal (Columbia University) | Inverse and Control Transport Problems]]<br />
| <!-- host --><br />
|-<br />
| '''Mar 11, 4pm, B239''' <br />
| [http://math.umn.edu/~luskin Mitchell Luskin] (University of Minnesota)<br />
| [[Colloquia#September 11: Mitchell Luskin (University of Minnesota) | Mathematical Modeling of Incommensurate 2D Materials]]<br />
| Li<br />
|-<br />
| Mar 18 <br />
| [https://pantherfile.uwm.edu/hinow/www/ Peter Hinow] (UW-Milwaukee)<br />
| [[Applied/ACMS/absS16#Peter Hinow (UW-Milwaukee) | Aspects of mathematical modeling of drug delivery]]<br />
| Saverio<br />
|-<br />
| Mar 25 <br />
| Spring break <br />
| <br />
| <br />
|-<br />
| Apr 8 <br />
| [http://math.mit.edu/~dunkel/ Jörn Dunkel] (MIT)<br />
| [[Applied/ACMS/absS16#Jörn Dunkel (MIT) | Pattern formation in soft and biological matter]] <br />
| Saverio<br />
|-<br />
| Apr 15 <br />
| [http://wid.wisc.edu/research/sysbio/labs/vetsigian-lab/ Kalin Vetsigian] (UW)<br />
| [[Applied/ACMS/absS16#Kalin Vetsigian (UW) | Interactions and dynamics in communities of antibiotic producing bacteria]]<br />
| Saverio<br />
|-<br />
| '''Apr 19, 2:25pm, room B341 Van Vleck'''<br />
| [http://www.riken.jp/theobio/en/member/mochi.html Atsushi Mochizuki] (RIKEN, Japan) <br />
| [[Applied/ACMS/absS16#Atsushi Mochizuki (RIKEN, Japan) | Dynamics of complex biological systems determined/controlled by minimal subsets of molecules in regulatory networks]]<br />
| Craciun<br />
|-<br />
| '''Apr 21, 4pm, 901'''<br />
| [http://engineering.ucsb.edu/~mgroup Igor Mezic] (UC Santa Barbara)<br />
| [[Applied/ACMS/absS16#Igor Mezic (UC Santa Barbara) | Koopman Operator Theory in Fluid Mechanics]]<br />
| Budisic, Jean-Luc<br />
|-<br />
| Apr 22 <br />
| [http://wid.wisc.edu/profile/sushmita-roy/ Sushmita Roy] (UW)<br />
| [[Applied/ACMS/absS16#Sushmita Roy (UW) | TBA]]<br />
| Saverio<br />
|-<br />
| '''Apr 29, 4pm, B239''' <br />
| [http://www.physics.upenn.edu/~kamien/kamiengroup/ Randall Kamien] (U Penn)<br />
| [[Applied/ACMS/absS16#Randall Kamien (U Penn) | Liquid crystals and their (algebraic) topology]] <br />
| Saverio<br />
|-<br />
| '''Mon. May 2'''<br />
| [http://www.ing.unitn.it/~toroe/ Eleuterio Toro] (U Trento) <br />
| [[Applied/ACMS/absS16#Eleuterio Toro (U Trento) | A flux splitting approach to a class of hyperbolic systems]] <br />
| Jin<br />
|-<br />
| '''Wed. May 4'''<br />
| [http://perso-math.univ-mlv.fr/users/fermanian.clotilde/index_en.html Clotilde Fermanian Kammerer] (Insmi - CNRS) <br />
| [[Applied/ACMS/absS16#Clotilde Fermanian Kammerer (Insmi - CNRS) | TBA]] <br />
| Jin<br />
|-<br />
| May 6<br />
| [http://calinia.people.cofc.edu/ Annalisa Calini] (College of Charleston) <br />
| [[Applied/ACMS/absS16Annalisa Calini (College of Charleston) | TBA]] <br />
| Gloria Mari-Beffa<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=11834Applied/ACMS2016-04-18T20:41:02Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2016 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 22<br />
| [https://sites.google.com/a/eng.ucsd.edu/sgls/ Stefan Llewellyn Smith] (UCSD)<br />
| [[Applied/ACMS/absS16#Stefan Llewellyn-Smith (UCSD)| Hollow vortices]] <br />
| Saverio<br />
|-<br />
| Jan 29<br />
| [http://www.eg.bucknell.edu/physics/solomon.html Tom Solomon] (Bucknell)<br />
| [[Applied/ACMS/absS16#Tom Solomon (Bucknell)| Experimental studies of reaction front barriers in laminar flows ]]<br />
| Jean-Luc and Marko<br />
|-<br />
| Feb 5 <br />
| [http://www.math.ku.dk/~d.cappelletti/ Daniele Cappelletti] (KU) <br />
| [[Applied/ACMS/absS16#Daniele Cappelletti (KU)| Deterministic and stochastic reaction networks ]]<br />
| Craciun<br />
|-<br />
| Feb 12 <br />
| Lihui Chai (UCSB)<br />
| [[Applied/ACMS/absS16#Lihui Chai (UCSB)| Semiclassical limit of the Schrödinger-Poisson-Landau-Lifshitz-Gilbert system ]]<br />
| Qin<br />
|-<br />
| '''Feb 12, 4pm, B239'''<br />
|[http://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU) <br />
| [[Colloquia#February 12: Gautam Iyer (CMU)| Homogenization and Anomalous Diffusion]]<br />
| Jean-Luc<br />
|-<br />
| Feb 19 <br />
| [http://directory.engr.wisc.edu/me/Faculty/Roldan-alzate_Alejandro/ Alejandro Roldán-Alzate] (UW) <br />
| [[Applied/ACMS/absS16#Alejandro Roldan-Alzate (UW)| Non–invasive patient-specific cardiovascular fluid dynamics]]<br />
| Saverio<br />
|-<br />
| Feb 26 <br />
| [http://math.sjtu.edu.cn/Showteacher.aspx?id=19&info_lb=98 Yachun Li] (SJTU)<br />
| [[Applied/ACMS/absS16#Yachun Li (SJTU)| Vanishing viscosity limit of the compressible Isentropic Navier-Stokes equations with degenerate viscosities]] <br />
| Shi Jin<br />
|-<br />
| ''' Mar 4, 4pm, B239'''<br />
|[http://www.columbia.edu/~gb2030/ Guillaume Bal] (Columbia University)<br />
|[[Colloquia#September 11: Guillaume Bal (Columbia University) | Inverse and Control Transport Problems]]<br />
| <!-- host --><br />
|-<br />
| '''Mar 11, 4pm, B239''' <br />
| [http://math.umn.edu/~luskin Mitchell Luskin] (University of Minnesota)<br />
| [[Colloquia#September 11: Mitchell Luskin (University of Minnesota) | Mathematical Modeling of Incommensurate 2D Materials]]<br />
| Li<br />
|-<br />
| Mar 18 <br />
| [https://pantherfile.uwm.edu/hinow/www/ Peter Hinow] (UW-Milwaukee)<br />
| [[Applied/ACMS/absS16#Peter Hinow (UW-Milwaukee) | Aspects of mathematical modeling of drug delivery]]<br />
| Saverio<br />
|-<br />
| Mar 25 <br />
| Spring break <br />
| <br />
| <br />
|-<br />
| Apr 8 <br />
| [http://math.mit.edu/~dunkel/ Jörn Dunkel] (MIT)<br />
| [[Applied/ACMS/absS16#Jörn Dunkel (MIT) | Pattern formation in soft and biological matter]] <br />
| Saverio<br />
|-<br />
| Apr 15 <br />
| [http://wid.wisc.edu/research/sysbio/labs/vetsigian-lab/ Kalin Vetsigian] (UW)<br />
| [[Applied/ACMS/absS16#Kalin Vetsigian (UW) | Interactions and dynamics in communities of antibiotic producing bacteria]]<br />
| Saverio<br />
|-<br />
| '''Apr 19, 2:25pm, room B314 Van Vleck'''<br />
| [http://www.riken.jp/theobio/en/member/mochi.html Atsushi Mochizuki] (RIKEN, Japan) <br />
| [[Applied/ACMS/absS16#Atsushi Mochizuki (RIKEN, Japan) | Dynamics of complex biological systems determined/controlled by minimal subsets of molecules in regulatory networks]]<br />
| Craciun<br />
|-<br />
| '''Apr 21, 4pm, 901'''<br />
| [http://engineering.ucsb.edu/~mgroup Igor Mezic] (UC Santa Barbara)<br />
| [[Applied/ACMS/absS16#Igor Mezic (UC Santa Barbara) | Koopman Operator Theory in Fluid Mechanics]]<br />
| Budisic, Jean-Luc<br />
|-<br />
| Apr 22 <br />
| [http://wid.wisc.edu/profile/sushmita-roy/ Sushmita Roy] (UW)<br />
| [[Applied/ACMS/absS16#Sushmita Roy (UW) | TBA]]<br />
| Saverio<br />
|-<br />
| '''Apr 29, 4pm, B239''' <br />
| [http://www.physics.upenn.edu/~kamien/kamiengroup/ Randall Kamien] (U Penn)<br />
| [[Applied/ACMS/absS16#Randall Kamien (U Penn) | Liquid crystals and their (algebraic) topology]] <br />
| Saverio<br />
|-<br />
| '''Mon. May 2'''<br />
| [http://www.ing.unitn.it/~toroe/ Eleuterio Toro] (U Trento) <br />
| [[Applied/ACMS/absS16#Eleuterio Toro (U Trento) | A flux splitting approach to a class of hyperbolic systems]] <br />
| Jin<br />
|-<br />
| '''Wed. May 4'''<br />
| [http://perso-math.univ-mlv.fr/users/fermanian.clotilde/index_en.html Clotilde Fermanian Kammerer] (Insmi - CNRS) <br />
| [[Applied/ACMS/absS16#Clotilde Fermanian Kammerer (Insmi - CNRS) | TBA]] <br />
| Jin<br />
|-<br />
| May 6<br />
| [http://calinia.people.cofc.edu/ Annalisa Calini] (College of Charleston) <br />
| [[Applied/ACMS/absS16Annalisa Calini (College of Charleston) | TBA]] <br />
| Gloria Mari-Beffa<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS16&diff=11758Applied/ACMS/absS162016-04-06T21:20:54Z<p>Craciun: </p>
<hr />
<div>= ACMS Abstracts: Spring 2016 =<br />
<br />
=== Stefan Llewellyn Smith (UCSD) ===<br />
<br />
''Hollow vortices''<br />
<br />
Hollow vortices are vortices whose interior is at rest. They posses vortex sheets on their boundaries and can be viewed as a desingularization of point vortices. After giving a history of point vortices, we obtain exact solutions for hollow vortices in linear and nonlinear strain and examine the properties of streets of hollow vortices. The former can be viewed as a canonical example of a hollow vortex in an arbitrary flow, and its stability properties depend on a single non-dimensional parameter. In the latter case, we reexamine the hollow vortex street of Baker, Saffman and Sheffield and examine its stability to arbitrary disturbances, and then investigate the double hollow vortex street. Implications and extensions of this work are discussed.<br />
<br />
=== Tom Solomon (Bucknell) ===<br />
<br />
''Experimental studies of reaction front barriers in laminar flows''<br />
<br />
We present studies of the effects of vortex-dominated fluid flows on the motion of reaction fronts produced by the excitable Belousov-Zhabotinsky reaction. The results of these experiments have applications for advection-reaction-diffusion dynamics in a wide range of systems including microfluidic chemical reactors, cellular-scale processes in biological systems, and blooms of phytoplankton in the oceans. To predict the behavior of reaction fronts, we adapt tools used to describe passive mixing.In particular, the concept of an invariant manifold is extended to account for reactive burning. Burning invariant manifolds (BIMs) are predicted as one-way barriers that locally block the motion of reaction fronts. These ideas are tested and illustrated experimentally in a chain of alternating vortices, a spatially-random flow, vortex flows with imposed winds, and a three-dimensional, nested vortex flow. We also discuss the applicability of BIM theory to the motion of bacteria in fluid flows.<br />
<br />
=== Daniele Cappelletti (KU) ===<br />
<br />
''Deterministic and stochastic reaction networks''<br />
<br />
Mathematical models of biochemical reaction networks are of great interest for the analysis of experimental data and theoretical biochemistry. Moreover, such models can be applied in a broader framework than that provided by biology. The classical deterministic model of a reaction network is a system of ordinary differential equations, and the standard stochastic model is a continuous-time Markov chain. A relationship between the dynamics of the two models can be found for compact time intervals, while the asymptotic behaviours of the two models may differ greatly. I will give an overview of these problems and show some recent development.<br />
<br />
=== Lihui Chai (UCSB) ===<br />
<br />
''Semiclassical limit of the Schrödinger-Poisson-Landau-Lifshitz-Gilbert system''<br />
<br />
The Schrödinger-Poisson-Landau-Lifshitz-Gilbert (SPLLG) system is an effective microscopic model that describes the coupling between conduction electron spins and the magnetization in ferromagnetic materials. This system has been used in connection to the study of spin transfer and magnetization reversal in ferromagnetic materials. In this paper, we rigorously derive the Vlasov-Poisson-Landau-Lifshitz-Glibert system as the semiclassical limit of SPLLG. The major difficulties come from the presence of the spin-magnetization coupling and the discontinuities of the magnetization at the boundary of the material. To overcome these difficulties, we first take the semiclassical limit (vanishing Planck constant) of a smoothed SPLLG system, and then the limit of vanishing smoothing parameter. As a byproduct, we prove the local existence and uniqueness of classical solutions to the smoothed SPLLG system.<br />
<br />
=== Alejandro Roldan-Alzate (UW) ===<br />
<br />
''Non–invasive patient-specific cardiovascular fluid dynamics''<br />
<br />
Comprehensive characterization and quantification of blood flow is essential for understanding the function of the cardiovascular system under normal and diseased conditions. This provides important information not only for the diagnosis and treatment planning of different cardiovascular diseases but also for the design of cardiovascular devices. However, the anatomical complexity and multidirectional nature of physiological and pathological hemodynamics makes non-invasive characterization and quantification of blood flow difficult and challenging. Doppler ultrasound, a standard imaging technique, is limited to providing information on large vessels and calculating instantaneous average flow within the cardiac cycle. Magnetic resonance imaging (MRI) is increasingly being used for fluid dynamics analyses of cardiovascular diseases, including pulmonary arterial hypertension, portal hypertension and congenital heart diseases. Although two-dimensional (2D) phase contrast (PC) magnetic resonance imaging (MRI) measures velocity across a plane, it is still limited in its ability to fully characterize these complex flow systems. Four- dimensional (4D) flow MRI obtains velocity measurements in three dimensions throughout the entire cardiac cycle. Several attempts have been made to non-invasively characterize the blood flow dynamics of different cardiovascular diseases using the combination of medical imaging and computational fluid dynamics modeling (CFD). Idealized geometries, as well as patient-specific anatomies, have been used for computational simulations, which have improved the understanding of the fluid dynamics phenomena in different vascular territories. While CFD modeling can provide powerful insights and the potential for simulating different physiological and pathological conditions in the cardiovascular system, it is currently not reliable for use in clinical care. Based on different studies, additional work is needed to verify the accuracy of current CFD approaches or identify and address current shortcomings. The overall purpose of this research is to develop, implement and validate non-invasive flow analysis methodologies to assess cardiovascular flow dynamics, using a combination of 4D flow MRI, numerical simulations and patient-specific physical models. In this seminar, multidisciplinary work will be presented first, where different cardiovascular pathologies have been studied, such as congenital heart disease and portal hypertension using in vivo, in vitro and computational models. Second, some advances will be presented and a future outlook into the valuable contribution of engineering in the medical imaging and diagnostic technology will be provided.<br />
<br />
=== Yachun Li (SJTU) ===<br />
<br />
''Vanishing viscosity limit of the compressible Isentropic Navier-Stokes equations with degenerate viscosities''<br />
<br />
In this talk we first establish the local-in-time well-posedness of the unique regular solution to the compressible isentropic Navier-Stokes equations with density-dependent viscosities in a power law and with vacuum appearing in some open set or at the far field, then after establishing uniform energy-type estimates with respect to the viscosity coefficients for the regular solutions we prove the convergence of the regular solution of the Navier-Stokes equations to that of the Euler equations with arbitrarily large data containing vacuum.<br />
<br />
=== Peter Hinow (UW-Milwaukee) ===<br />
<br />
''Aspects of mathematical modeling of drug delivery''<br />
<br />
There are a variety of devices for the delivery of pharmaceutical substances, tablets of course being the most prominent. Pharmaceutical scientists and physicians have formulated goals, such as release of a drug in a controlled fashion over an extended period of time or the targeted delivery of a drug to a specific site in a patient’s body. Since experiments with these delivery devices can be costly and sometimes only partially conclusive, mathematical modeling plays a considerable role in understanding the mechanisms behind experimental release profiles, and in developing delivery systems. We present our works on drug delivery by matrix tablets and targeted drug delivery to the brain. This is joint work with Ami Radunskaya (Department of Mathematics, Pomona College, Claremont, CA) and Ian Tucker (School of Pharmacy, University of Otago, Dunedin, New Zealand), and has been supported by NSF grants DMS 1016214 and DMS 1016136 .<br />
<br />
=== Jorn Dunkel (MIT) ===<br />
<br />
''Pattern formation in soft and biological matter''<br />
<br />
Identifying the generic ordering principles that govern multicellular and intracellular dynamics is essential for separating universal from system-specific aspects in the physics of living organisms. In this talk, we will survey and compare three recently proposed nonlinear continuum theories, which aim to describe pattern formation and topological defect structures in soft elastic bilayer materials, dense bacterial suspensions and ATP-driven active liquid crystals. We will discuss the phase diagrams of the three models, relate their predictions to experiments, and emphasize the underlying universality ideas. The good agreement with experimental data supports the idea that non-equilibrium pattern formation in a broad range of soft and active matter systems can be described effectively within the same class of higher-order partial differential equations.<br />
<br />
=== Kalin Vetsigian (UW) ===<br />
<br />
''Interactions and dynamics in communities of antibiotic producing bacteria''<br />
<br />
How microbial diversity is generated and maintained is a fundamental ecological question that can be studied through laboratory microcosm experiments and mathematical modeling. We developed a platform for measuring interactions and dynamics in communities of antibiotic producing bacteria and examined patterns of microbial interactions and frequency-dependent selection. We discovered high levels of antibiotic inhibition, high levels of antibiotic degradation, and frequent bistability among pairs of strains. This data led to the theoretical realization that the interplay between antibiotic production and degradation can lead to robust diversity maintenance through simple motifs that contain bistable pairs. Further computer simulations showed that evolution of antibiotic production and degradation capabilities can lead to spontaneous emergence of diversity and complex eco-evolutionary dynamics in simple environments with a single food source.<br />
<br />
=== Atsushi Mochizuki (RIKEN, Japan) ===<br />
<br />
''Dynamics of complex biological systems determined/controlled by minimal subsets of molecules in regulatory networks''<br />
<br />
Modern biology provides many networks describing regulations between a large number of species of molecules. It is widely believed that the dynamics of molecular activities based on such regulatory networks are the origin of biological functions. In this study we develop a new theory to provide an important aspect of dynamics from information of regulatory linkages alone. We show that the "feedback vertex set" (FVS) of a regulatory network is a set of "determining nodes" of the dynamics. It assures that (i) any long-term dynamical behavior of the whole system, such as steady states, periodic oscillations or quasi-periodic oscillations, can be identified by measurements of a subset of molecules in the network, and that (ii) the subset is determined from the regulatory linkage alone. For example, dynamical attractors possibly generated by a signal transduction network with 113 molecules can be identified by measurement of the activity of only 5 molecules, if the information on the network structure is correct. We also demonstrate that controlling the dynamics of the FVS is sufficient to switch the dynamics of the whole system from one attractor to others, distinct from the original.<br />
<br />
Further Reading:<br />
<br />
Mochizuki A., Fiedler B., Kurosawa G. and Saito D. (2013) Dynamics and control at feedback vertex sets. J. Theor. Biol. 335: 130-146.<br />
<br />
=== Randall Kamien (U Penn) ===<br />
<br />
''Liquid crystals and their (algebraic) topology''<br />
<br />
Liquid Crystals, the materials in your iPhone, are complex materials with varying degrees of internal order. I will discuss and demonstrate how algebraic topology can be used to identify and characterize long-lived configurations. I will also describe how conic sections naturally arise in these structures as intersections of simple polynomials.<br />
<br />
=== Eleuterio Toro (U Trento) ===<br />
<br />
''A flux splitting approach to a class of hyperbolic systems'' <br />
<br />
This talk is based on a recently proposed flux vector splitting method for the Euler equations which, compared to existing splitting methods, has some distinctive advantages, such as exact recognition of stationary isolated contact/shear waves, simplicity, robustness and efficiency. Distinguishing features of the new flux splitting approach are: complete separation of pressure from advection terms and identification of a reduced pressure system that furnishes all required information for constructing the full numerical flux in a simple manner. The resulting first-order method was originally proposed for the 1D Euler equations for ideal gases. In this talk I will first present the scheme as applied to the 3D Euler equations with general equation of state. Then I shall describe its extension to high-order of accuracy in both space and time, on unstructured meshes, using the ADER approach. Performance of the resulting method is illustrated through some carefully chosen test problems. I finish this presentation by mentioning extensions of this novel flux splitting approach to other hyperbolic systems, such as the MHD equations and the Baer-Nunziato equations for compressible multiphase flows.</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS16&diff=11757Applied/ACMS/absS162016-04-06T21:18:33Z<p>Craciun: </p>
<hr />
<div>= ACMS Abstracts: Spring 2016 =<br />
<br />
=== Stefan Llewellyn Smith (UCSD) ===<br />
<br />
''Hollow vortices''<br />
<br />
Hollow vortices are vortices whose interior is at rest. They posses vortex sheets on their boundaries and can be viewed as a desingularization of point vortices. After giving a history of point vortices, we obtain exact solutions for hollow vortices in linear and nonlinear strain and examine the properties of streets of hollow vortices. The former can be viewed as a canonical example of a hollow vortex in an arbitrary flow, and its stability properties depend on a single non-dimensional parameter. In the latter case, we reexamine the hollow vortex street of Baker, Saffman and Sheffield and examine its stability to arbitrary disturbances, and then investigate the double hollow vortex street. Implications and extensions of this work are discussed.<br />
<br />
=== Tom Solomon (Bucknell) ===<br />
<br />
''Experimental studies of reaction front barriers in laminar flows''<br />
<br />
We present studies of the effects of vortex-dominated fluid flows on the motion of reaction fronts produced by the excitable Belousov-Zhabotinsky reaction. The results of these experiments have applications for advection-reaction-diffusion dynamics in a wide range of systems including microfluidic chemical reactors, cellular-scale processes in biological systems, and blooms of phytoplankton in the oceans. To predict the behavior of reaction fronts, we adapt tools used to describe passive mixing.In particular, the concept of an invariant manifold is extended to account for reactive burning. Burning invariant manifolds (BIMs) are predicted as one-way barriers that locally block the motion of reaction fronts. These ideas are tested and illustrated experimentally in a chain of alternating vortices, a spatially-random flow, vortex flows with imposed winds, and a three-dimensional, nested vortex flow. We also discuss the applicability of BIM theory to the motion of bacteria in fluid flows.<br />
<br />
=== Daniele Cappelletti (KU) ===<br />
<br />
''Deterministic and stochastic reaction networks''<br />
<br />
Mathematical models of biochemical reaction networks are of great interest for the analysis of experimental data and theoretical biochemistry. Moreover, such models can be applied in a broader framework than that provided by biology. The classical deterministic model of a reaction network is a system of ordinary differential equations, and the standard stochastic model is a continuous-time Markov chain. A relationship between the dynamics of the two models can be found for compact time intervals, while the asymptotic behaviours of the two models may differ greatly. I will give an overview of these problems and show some recent development.<br />
<br />
=== Lihui Chai (UCSB) ===<br />
<br />
''Semiclassical limit of the Schrödinger-Poisson-Landau-Lifshitz-Gilbert system''<br />
<br />
The Schrödinger-Poisson-Landau-Lifshitz-Gilbert (SPLLG) system is an effective microscopic model that describes the coupling between conduction electron spins and the magnetization in ferromagnetic materials. This system has been used in connection to the study of spin transfer and magnetization reversal in ferromagnetic materials. In this paper, we rigorously derive the Vlasov-Poisson-Landau-Lifshitz-Glibert system as the semiclassical limit of SPLLG. The major difficulties come from the presence of the spin-magnetization coupling and the discontinuities of the magnetization at the boundary of the material. To overcome these difficulties, we first take the semiclassical limit (vanishing Planck constant) of a smoothed SPLLG system, and then the limit of vanishing smoothing parameter. As a byproduct, we prove the local existence and uniqueness of classical solutions to the smoothed SPLLG system.<br />
<br />
=== Alejandro Roldan-Alzate (UW) ===<br />
<br />
''Non–invasive patient-specific cardiovascular fluid dynamics''<br />
<br />
Comprehensive characterization and quantification of blood flow is essential for understanding the function of the cardiovascular system under normal and diseased conditions. This provides important information not only for the diagnosis and treatment planning of different cardiovascular diseases but also for the design of cardiovascular devices. However, the anatomical complexity and multidirectional nature of physiological and pathological hemodynamics makes non-invasive characterization and quantification of blood flow difficult and challenging. Doppler ultrasound, a standard imaging technique, is limited to providing information on large vessels and calculating instantaneous average flow within the cardiac cycle. Magnetic resonance imaging (MRI) is increasingly being used for fluid dynamics analyses of cardiovascular diseases, including pulmonary arterial hypertension, portal hypertension and congenital heart diseases. Although two-dimensional (2D) phase contrast (PC) magnetic resonance imaging (MRI) measures velocity across a plane, it is still limited in its ability to fully characterize these complex flow systems. Four- dimensional (4D) flow MRI obtains velocity measurements in three dimensions throughout the entire cardiac cycle. Several attempts have been made to non-invasively characterize the blood flow dynamics of different cardiovascular diseases using the combination of medical imaging and computational fluid dynamics modeling (CFD). Idealized geometries, as well as patient-specific anatomies, have been used for computational simulations, which have improved the understanding of the fluid dynamics phenomena in different vascular territories. While CFD modeling can provide powerful insights and the potential for simulating different physiological and pathological conditions in the cardiovascular system, it is currently not reliable for use in clinical care. Based on different studies, additional work is needed to verify the accuracy of current CFD approaches or identify and address current shortcomings. The overall purpose of this research is to develop, implement and validate non-invasive flow analysis methodologies to assess cardiovascular flow dynamics, using a combination of 4D flow MRI, numerical simulations and patient-specific physical models. In this seminar, multidisciplinary work will be presented first, where different cardiovascular pathologies have been studied, such as congenital heart disease and portal hypertension using in vivo, in vitro and computational models. Second, some advances will be presented and a future outlook into the valuable contribution of engineering in the medical imaging and diagnostic technology will be provided.<br />
<br />
=== Yachun Li (SJTU) ===<br />
<br />
''Vanishing viscosity limit of the compressible Isentropic Navier-Stokes equations with degenerate viscosities''<br />
<br />
In this talk we first establish the local-in-time well-posedness of the unique regular solution to the compressible isentropic Navier-Stokes equations with density-dependent viscosities in a power law and with vacuum appearing in some open set or at the far field, then after establishing uniform energy-type estimates with respect to the viscosity coefficients for the regular solutions we prove the convergence of the regular solution of the Navier-Stokes equations to that of the Euler equations with arbitrarily large data containing vacuum.<br />
<br />
=== Peter Hinow (UW-Milwaukee) ===<br />
<br />
''Aspects of mathematical modeling of drug delivery''<br />
<br />
There are a variety of devices for the delivery of pharmaceutical substances, tablets of course being the most prominent. Pharmaceutical scientists and physicians have formulated goals, such as release of a drug in a controlled fashion over an extended period of time or the targeted delivery of a drug to a specific site in a patient’s body. Since experiments with these delivery devices can be costly and sometimes only partially conclusive, mathematical modeling plays a considerable role in understanding the mechanisms behind experimental release profiles, and in developing delivery systems. We present our works on drug delivery by matrix tablets and targeted drug delivery to the brain. This is joint work with Ami Radunskaya (Department of Mathematics, Pomona College, Claremont, CA) and Ian Tucker (School of Pharmacy, University of Otago, Dunedin, New Zealand), and has been supported by NSF grants DMS 1016214 and DMS 1016136 .<br />
<br />
=== Jorn Dunkel (MIT) ===<br />
<br />
''Pattern formation in soft and biological matter''<br />
<br />
Identifying the generic ordering principles that govern multicellular and intracellular dynamics is essential for separating universal from system-specific aspects in the physics of living organisms. In this talk, we will survey and compare three recently proposed nonlinear continuum theories, which aim to describe pattern formation and topological defect structures in soft elastic bilayer materials, dense bacterial suspensions and ATP-driven active liquid crystals. We will discuss the phase diagrams of the three models, relate their predictions to experiments, and emphasize the underlying universality ideas. The good agreement with experimental data supports the idea that non-equilibrium pattern formation in a broad range of soft and active matter systems can be described effectively within the same class of higher-order partial differential equations.<br />
<br />
=== Kalin Vetsigian (UW) ===<br />
<br />
''Interactions and dynamics in communities of antibiotic producing bacteria''<br />
<br />
How microbial diversity is generated and maintained is a fundamental ecological question that can be studied through laboratory microcosm experiments and mathematical modeling. We developed a platform for measuring interactions and dynamics in communities of antibiotic producing bacteria and examined patterns of microbial interactions and frequency-dependent selection. We discovered high levels of antibiotic inhibition, high levels of antibiotic degradation, and frequent bistability among pairs of strains. This data led to the theoretical realization that the interplay between antibiotic production and degradation can lead to robust diversity maintenance through simple motifs that contain bistable pairs. Further computer simulations showed that evolution of antibiotic production and degradation capabilities can lead to spontaneous emergence of diversity and complex eco-evolutionary dynamics in simple environments with a single food source.<br />
<br />
=== Randall Kamien (U Penn) ===<br />
<br />
''Liquid crystals and their (algebraic) topology''<br />
<br />
Liquid Crystals, the materials in your iPhone, are complex materials with varying degrees of internal order. I will discuss and demonstrate how algebraic topology can be used to identify and characterize long-lived configurations. I will also describe how conic sections naturally arise in these structures as intersections of simple polynomials.<br />
<br />
=== Eleuterio Toro (U Trento) ===<br />
<br />
''A flux splitting approach to a class of hyperbolic systems'' <br />
<br />
This talk is based on a recently proposed flux vector splitting method for the Euler equations which, compared to existing splitting methods, has some distinctive advantages, such as exact recognition of stationary isolated contact/shear waves, simplicity, robustness and efficiency. Distinguishing features of the new flux splitting approach are: complete separation of pressure from advection terms and identification of a reduced pressure system that furnishes all required information for constructing the full numerical flux in a simple manner. The resulting first-order method was originally proposed for the 1D Euler equations for ideal gases. In this talk I will first present the scheme as applied to the 3D Euler equations with general equation of state. Then I shall describe its extension to high-order of accuracy in both space and time, on unstructured meshes, using the ADER approach. Performance of the resulting method is illustrated through some carefully chosen test problems. I finish this presentation by mentioning extensions of this novel flux splitting approach to other hyperbolic systems, such as the MHD equations and the Baer-Nunziato equations for compressible multiphase flows.<br />
<br />
=== Atsushi Mochizuki (RIKEN, Japan) ===<br />
<br />
"Dynamics of complex biological systems determined/controlled by minimal subsets of molecules in regulatory networks"<br />
<br />
Modern biology provides many networks describing regulations between a large number of species of molecules. It is widely believed that the dynamics of molecular activities based on such regulatory networks are the origin of biological functions. In this study we develop a new theory to provide an important aspect of dynamics from information of regulatory linkages alone. We show that the "feedback vertex set" (FVS) of a regulatory network is a set of "determining nodes" of the dynamics. It assures that (i) any long-term dynamical behavior of the whole system, such as steady states, periodic oscillations or quasi-periodic oscillations, can be identified by measurements of a subset of molecules in the network, and that (ii) the subset is determined from the regulatory linkage alone. For example, dynamical attractors possibly generated by a signal transduction network with 113 molecules can be identified by measurement of the activity of only 5 molecules, if the information on the network structure is correct. We also demonstrate that controlling the dynamics of the FVS is sufficient to switch the dynamics of the whole system from one attractor to others, distinct from the original.<br />
<br />
Further Reading:<br />
<br />
Mochizuki A., Fiedler B., Kurosawa G. and Saito D. (2013) Dynamics and control at feedback vertex sets. J. Theor. Biol. 335: 130-146.</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=11756Applied/ACMS2016-04-06T21:15:38Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2016 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 22<br />
| [https://sites.google.com/a/eng.ucsd.edu/sgls/ Stefan Llewellyn Smith] (UCSD)<br />
| [[Applied/ACMS/absS16#Stefan Llewellyn-Smith (UCSD)| Hollow vortices]] <br />
| Saverio<br />
|-<br />
| Jan 29<br />
| [http://www.eg.bucknell.edu/physics/solomon.html Tom Solomon] (Bucknell)<br />
| [[Applied/ACMS/absS16#Tom Solomon (Bucknell)| Experimental studies of reaction front barriers in laminar flows ]]<br />
| Jean-Luc and Marko<br />
|-<br />
| Feb 5 <br />
| [http://www.math.ku.dk/~d.cappelletti/ Daniele Cappelletti] (KU) <br />
| [[Applied/ACMS/absS16#Daniele Cappelletti (KU)| Deterministic and stochastic reaction networks ]]<br />
| Craciun<br />
|-<br />
| Feb 12 <br />
| Lihui Chai (UCSB)<br />
| [[Applied/ACMS/absS16#Lihui Chai (UCSB)| Semiclassical limit of the Schrödinger-Poisson-Landau-Lifshitz-Gilbert system ]]<br />
| Qin<br />
|-<br />
| '''Feb 12, 4pm, B239'''<br />
|[http://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU) <br />
| [[Colloquia#February 12: Gautam Iyer (CMU)| Homogenization and Anomalous Diffusion]]<br />
| Jean-Luc<br />
|-<br />
| Feb 19 <br />
| [http://directory.engr.wisc.edu/me/Faculty/Roldan-alzate_Alejandro/ Alejandro Roldán-Alzate] (UW) <br />
| [[Applied/ACMS/absS16#Alejandro Roldan-Alzate (UW)| Non–invasive patient-specific cardiovascular fluid dynamics]]<br />
| Saverio<br />
|-<br />
| Feb 26 <br />
| [http://math.sjtu.edu.cn/Showteacher.aspx?id=19&info_lb=98 Yachun Li] (SJTU)<br />
| [[Applied/ACMS/absS16#Yachun Li (SJTU)| Vanishing viscosity limit of the compressible Isentropic Navier-Stokes equations with degenerate viscosities]] <br />
| Shi Jin<br />
|-<br />
| ''' Mar 4, 4pm, B239'''<br />
|[http://www.columbia.edu/~gb2030/ Guillaume Bal] (Columbia University)<br />
|[[Colloquia#September 11: Guillaume Bal (Columbia University) | Inverse and Control Transport Problems]]<br />
| <!-- host --><br />
|-<br />
| '''Mar 11, 4pm, B239''' <br />
| [http://math.umn.edu/~luskin Mitchell Luskin] (University of Minnesota)<br />
| [[Colloquia#September 11: Mitchell Luskin (University of Minnesota) | Mathematical Modeling of Incommensurate 2D Materials]]<br />
| Li<br />
|-<br />
| Mar 18 <br />
| [https://pantherfile.uwm.edu/hinow/www/ Peter Hinow] (UW-Milwaukee)<br />
| [[Applied/ACMS/absS16#Peter Hinow (UW-Milwaukee) | Aspects of mathematical modeling of drug delivery]]<br />
| Saverio<br />
|-<br />
| Mar 25 <br />
| Spring break <br />
| <br />
| <br />
|-<br />
| Apr 8 <br />
| [http://math.mit.edu/~dunkel/ Jörn Dunkel] (MIT)<br />
| [[Applied/ACMS/absS16#Jörn Dunkel (MIT) | Pattern formation in soft and biological matter]] <br />
| Saverio<br />
|-<br />
| Apr 15 <br />
| [http://wid.wisc.edu/research/sysbio/labs/vetsigian-lab/ Kalin Vetsigian] (UW)<br />
| [[Applied/ACMS/absS16#Kalin Vetsigian (UW) | Interactions and dynamics in communities of antibiotic producing bacteria]]<br />
| Saverio<br />
|-<br />
| Apr 19<br />
| [http://www.riken.jp/theobio/en/member/mochi.html Atsushi Mochizuki] (RIKEN, Japan) <br />
| [[Applied/ACMS/absS16#Atsushi Mochizuki (RIKEN, Japan) | Dynamics of complex biological systems determined/controlled by minimal subsets of molecules in regulatory networks]]<br />
| Craciun<br />
|-<br />
| Apr 22 <br />
| [http://wid.wisc.edu/profile/sushmita-roy/ Sushmita Roy] (UW)<br />
| [[Applied/ACMS/absS16#Sushmita Roy (UW) | TBA]]<br />
| Saverio<br />
|-<br />
| '''Apr 29, 4pm, B239''' <br />
| [http://www.physics.upenn.edu/~kamien/kamiengroup/ Randall Kamien] (U Penn)<br />
| [[Applied/ACMS/absS16#Randall Kamien (U Penn) | Liquid crystals and their (algebraic) topology]] <br />
| Saverio<br />
|-<br />
| '''Mon. May 2'''<br />
| [http://www.ing.unitn.it/~toroe/ Eleuterio Toro] (U Trento) <br />
| [[Applied/ACMS/absS16#Eleuterio Toro (U Trento) | A flux splitting approach to a class of hyperbolic systems]] <br />
| Jin<br />
|-<br />
| '''Wed. May 4'''<br />
| [http://perso-math.univ-mlv.fr/users/fermanian.clotilde/index_en.html Clotilde Fermanian Kammerer] (Insmi - CNRS) <br />
| [[Applied/ACMS/absS16#Clotilde Fermanian Kammerer (Insmi - CNRS) | TBA]] <br />
| Jin<br />
|-<br />
| May 6<br />
| [http://calinia.people.cofc.edu/ Annalisa Calini] (College of Charleston) <br />
| [[Applied/ACMS/absS16Annalisa Calini (College of Charleston) | TBA]] <br />
| Gloria Mari-Beffa<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=11651Applied/ACMS2016-03-17T07:37:31Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2016 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 22<br />
| [https://sites.google.com/a/eng.ucsd.edu/sgls/ Stefan Llewellyn Smith] (UCSD)<br />
| [[Applied/ACMS/absS16#Stefan Llewellyn-Smith (UCSD)| Hollow vortices]] <br />
| Saverio<br />
|-<br />
| Jan 29<br />
| [http://www.eg.bucknell.edu/physics/solomon.html Tom Solomon] (Bucknell)<br />
| [[Applied/ACMS/absS16#Tom Solomon (Bucknell)| Experimental studies of reaction front barriers in laminar flows ]]<br />
| Jean-Luc and Marko<br />
|-<br />
| Feb 5 <br />
| [http://www.math.ku.dk/~d.cappelletti/ Daniele Cappelletti] (KU) <br />
| [[Applied/ACMS/absS16#Daniele Cappelletti (KU)| Deterministic and stochastic reaction networks ]]<br />
| Craciun<br />
|-<br />
| Feb 12 <br />
| Lihui Chai (UCSB)<br />
| [[Applied/ACMS/absS16#Lihui Chai (UCSB)| Semiclassical limit of the Schrödinger-Poisson-Landau-Lifshitz-Gilbert system ]]<br />
| Qin<br />
|-<br />
| '''Feb 12, 4pm, B239'''<br />
|[http://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU) <br />
| [[Colloquia#February 12: Gautam Iyer (CMU)| Homogenization and Anomalous Diffusion]]<br />
| Jean-Luc<br />
|-<br />
| Feb 19 <br />
| [http://directory.engr.wisc.edu/me/Faculty/Roldan-alzate_Alejandro/ Alejandro Roldán-Alzate] (UW) <br />
| [[Applied/ACMS/absS16#Alejandro Roldan-Alzate (UW)| Non–invasive patient-specific cardiovascular fluid dynamics]]<br />
| Saverio<br />
|-<br />
| Feb 26 <br />
| [http://math.sjtu.edu.cn/Showteacher.aspx?id=19&info_lb=98 Yachun Li] (SJTU)<br />
| [[Applied/ACMS/absS16#Yachun Li (SJTU)| Vanishing viscosity limit of the compressible Isentropic Navier-Stokes equations with degenerate viscosities]] <br />
| Shi Jin<br />
|-<br />
| ''' Mar 4, 4pm, B239'''<br />
|[http://www.columbia.edu/~gb2030/ Guillaume Bal] (Columbia University)<br />
|[[Colloquia#September 11: Guillaume Bal (Columbia University) | Inverse and Control Transport Problems]]<br />
| <!-- host --><br />
|-<br />
| '''Mar 11, 4pm, B239''' <br />
| [http://math.umn.edu/~luskin Mitchell Luskin] (University of Minnesota)<br />
| [[Colloquia#September 11: Mitchell Luskin (University of Minnesota) | Mathematical Modeling of Incommensurate 2D Materials]]<br />
| Li<br />
|-<br />
| Mar 18 <br />
| [https://pantherfile.uwm.edu/hinow/www/ Peter Hinow] (UW-Milwaukee)<br />
| [[Applied/ACMS/absS16#Peter Hinow (UW-Milwaukee) | Aspects of mathematical modeling of drug delivery]]<br />
| Saverio<br />
|-<br />
| Mar 25 <br />
| Spring break <br />
| <br />
| <br />
|-<br />
| Apr 1 <br />
| <br />
| <br />
| <br />
|-<br />
| Apr 8 <br />
| [http://math.mit.edu/~dunkel/ Jörn Dunkel] (MIT)<br />
| [[Applied/ACMS/absS16#Jörn Dunkel (MIT) | TBA]] <br />
| Saverio<br />
|-<br />
| Apr 15 <br />
| [http://wid.wisc.edu/research/sysbio/labs/vetsigian-lab/ Kalin Vetsigian] (UW)<br />
| [[Applied/ACMS/absS16#Kalin Vetsigian (UW) | TBA]]<br />
| Saverio<br />
|-<br />
| Apr 19<br />
| [http://www.riken.jp/theobio/en/member/mochi.html Atsushi Mochizuki] (RIKEN, Japan) <br />
| [[Applied/ACMS/absS16#Atsushi Mochizuki (RIKEN, Japan)| TBA ]]<br />
| Craciun<br />
|-<br />
| Apr 22 <br />
| [http://wid.wisc.edu/profile/sushmita-roy/ Sushmita Roy] (UW)<br />
| [[Applied/ACMS/absS16#Sushmita Roy (UW) | TBA]]<br />
| Saverio<br />
|-<br />
| '''Apr 29, 4pm, B239''' <br />
| [http://www.physics.upenn.edu/~kamien/kamiengroup/ Randall Kamien] (U Penn)<br />
| [[Applied/ACMS/absS16#Randall Kamien (U Penn) | TBA]] <br />
| Saverio<br />
|-<br />
| '''Mon. May 2'''<br />
| [http://www.ing.unitn.it/~toroe/ Eleuterio Toro] (U Trento) <br />
| [[Applied/ACMS/absS16#Eleuterio Toro (U Trento) | A flux splitting approach to a class of hyperbolic systems]] <br />
| Jin<br />
|-<br />
| '''Wed. May 4'''<br />
| [http://perso-math.univ-mlv.fr/users/fermanian.clotilde/index_en.html Clotilde Fermanian Kammerer] (Insmi - CNRS) <br />
| [[Applied/ACMS/absS16#Clotilde Fermanian Kammerer (Insmi - CNRS) | TBA]] <br />
| Jin<br />
|-<br />
| May 6<br />
| [http://calinia.people.cofc.edu/ Annalisa Calini] (College of Charleston) <br />
| [[Applied/ACMS/absS16Annalisa Calini (College of Charleston) | TBA]] <br />
| Gloria Mari-Beffa<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=11561Applied/ACMS2016-02-27T02:20:03Z<p>Craciun: </p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2016 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 22<br />
| [https://sites.google.com/a/eng.ucsd.edu/sgls/ Stefan Llewellyn Smith] (UCSD)<br />
| [[Applied/ACMS/absS16#Stefan Llewellyn-Smith (UCSD)| Hollow vortices]] <br />
| Saverio<br />
|-<br />
| Jan 29<br />
| [http://www.eg.bucknell.edu/physics/solomon.html Tom Solomon] (Bucknell)<br />
| [[Applied/ACMS/absS16#Tom Solomon (Bucknell)| Experimental studies of reaction front barriers in laminar flows ]]<br />
| Jean-Luc and Marko<br />
|-<br />
| Feb 5 <br />
| [http://www.math.ku.dk/~d.cappelletti/ Daniele Cappelletti] (KU) <br />
| [[Applied/ACMS/absS16#Daniele Cappelletti (KU)| Deterministic and stochastic reaction networks ]]<br />
| Craciun<br />
|-<br />
| Feb 12 <br />
| Lihui Chai (UCSB)<br />
| [[Applied/ACMS/absS16#Lihui Chai (UCSB)| Semiclassical limit of the Schrödinger-Poisson-Landau-Lifshitz-Gilbert system ]]<br />
| Qin<br />
|-<br />
| '''Feb 12, 4pm, B239'''<br />
|[http://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU) <br />
| [[Colloquia#February 12: Gautam Iyer (CMU)| Homogenization and Anomalous Diffusion]]<br />
| Jean-Luc<br />
|-<br />
| Feb 19 <br />
| [http://directory.engr.wisc.edu/me/Faculty/Roldan-alzate_Alejandro/ Alejandro Roldán-Alzate] (UW) <br />
| [[Applied/ACMS/absS16#Alejandro Roldan-Alzate (UW)| Non–invasive patient-specific cardiovascular fluid dynamics]]<br />
| Saverio<br />
|-<br />
| Feb 26 <br />
| [http://math.sjtu.edu.cn/Showteacher.aspx?id=19&info_lb=98 Yachun Li] (SJTU)<br />
| [[Applied/ACMS/absS16#Yachun Li (SJTU)| Vanishing viscosity limit of the compressible Isentropic Navier-Stokes equations with degenerate viscosities]] <br />
| Shi Jin<br />
|-<br />
| ''' Mar 4, 4pm, B239'''<br />
|[http://www.columbia.edu/~gb2030/ Guillaume Bal] (Columbia University)<br />
| <!-- [[Colloquia#September 11: Speaker (University) | title]] --><br />
| <!-- host --><br />
|-<br />
| '''Mar 11, 4pm, B239''' <br />
| [http://math.umn.edu/~luskin Mitchell Luskin] (University of Minnesota)<br />
| <!-- [[Colloquia#September 11: Speaker (University) | title]] --><br />
| Li<br />
|-<br />
| Mar 18 <br />
| <!-- [webpage Speaker Name] (University) --> <br />
| <!-- [[Colloquia#September 11: Speaker (University) | title]] --><br />
| <!-- host --><br />
|-<br />
| Mar 25 <br />
| Spring break <br />
| <br />
| <br />
|-<br />
| Apr 1 <br />
| [http://calinia.people.cofc.edu/ Annalisa Calini] (College of Charleston) <br />
| [[Colloquia#April 1: Annalisa Calini (College of Charleston) | TBA]] <br />
| Gloria Mari-Beffa<br />
|-<br />
| Apr 8 <br />
| [http://math.mit.edu/~dunkel/ Jörn Dunkel] (MIT)<br />
| [[Applied/ACMS/absS16#Jörn Dunkel (MIT) | TBA]] <br />
| Saverio<br />
|-<br />
| Apr 15 <br />
| [http://wid.wisc.edu/research/sysbio/labs/vetsigian-lab/ Kalin Vetsigian] (UW)<br />
| [[Applied/ACMS/absS16#Kalin Vetsigian (UW) | TBA]]<br />
| Saverio<br />
|-<br />
| Apr 18<br />
| [http://www.riken.jp/theobio/en/member/mochi.html Atsushi Mochizuki] (RIKEN, Japan) <br />
| [[Applied/ACMS/absS16#Atsushi Mochizuki (RIKEN, Japan)| TBA ]]<br />
| Craciun<br />
|-<br />
| Apr 22 <br />
| <!-- [webpage Speaker Name] (University) --> <br />
| <!-- [[Colloquia#September 11: Speaker (University) | title]] --><br />
| <!-- host --><br />
|-<br />
| '''Apr 29, 4pm, B239''' <br />
| [http://www.physics.upenn.edu/~kamien/kamiengroup/ Randall Kamien] (U Penn)<br />
| [[Applied/ACMS/absS16#Randall Kamien (U Penn) | TBA]] <br />
| Saverio<br />
|-<br />
| '''Mon. May 2'''<br />
| [http://www.ing.unitn.it/~toroe/ Eleuterio Toro] (U Trento) <br />
| [[Applied/ACMS/absS16#Eleuterio Toro (U Trento) | TBA]] <br />
| Jin<br />
|-<br />
| '''Wed. May 4'''<br />
| [http://perso-math.univ-mlv.fr/users/fermanian.clotilde/index_en.html Clotilde Fermanian Kammerer] (Insmi - CNRS) <br />
| [[Applied/ACMS/absS16#Clotilde Fermanian Kammerer (Insmi - CNRS) | TBA]] <br />
| Jin<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=9639Applied/ACMS2015-04-10T21:56:43Z<p>Craciun: /* Spring 2015 Semester */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://lists.math.wisc.edu/listinfo/acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2015 Semester ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Jan 23<br />
|[http://www.maths.dundee.ac.uk/ikyza/IreneKyza/ Irene Kyza] (U Dundee)<br />
|''[[Applied/ACMS/absS15#Irene Kyza (U Dundee)|Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control]]''<br />
|Shi Jin <br />
|-<br />
|Jan 30<br />
|[http://www.aos.wisc.edu/~dvimont/ Daniel Vimont] (UW)<br />
|''[[Applied/ACMS/absS15#Daniel Vimont (UW)|Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events]]''<br />
|Sam, Saverio<br />
|<br />
|-<br />
|Feb 13<br />
|[http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] (UW)<br />
|''[[Applied/ACMS/absS15#Saverio Spagnolie (UW)|Sedimentation in viscous fluids: flexible filaments and boundary effects]]''<br />
|<br />
|-<br />
|Feb 20<br />
|[http://jbfreund.mechse.illinois.edu/ Jonathan Freund] (U Illinois)<br />
|''[[Applied/ACMS/absS15#Jonathan Freund (UIUC)|Adjoint-based optimization for understanding and reducing flow noise]]''<br />
|Saverio<br />
|-<br />
|Feb 27<br />
|[http://people.math.umass.edu/~markos/ Markos Katsoulakis] (U Mass Amherst)<br />
|''[[Applied/ACMS/absS15#Markos Katsoulakis (U Mass Amherst)|Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics]]''<br />
|Shi Jin<br />
|-<br />
|Mar 6<br />
|[https://www.ljll.math.upmc.fr/~coquel/node2.html Frederic Coquel] (Ecole Polytechnique Paris)<br />
|''[[Applied/ACMS/absS15#Frederic Coquel (Ecole Polytechnique Paris)|Jin and Xin's Relaxation Framework with Defect Measure Corrections]]''<br />
|Shi Jin<br />
|-<br />
|Mar 13<br />
|[http://dauns.math.tulane.edu/~ljf/ Lisa Fauci] (Tulane)<br />
|''[[Applied/ACMS/absS15#Lisa Fauci (Tulane)|Flagellar motility: negotiating sticky elastic bonds and viscoelastic networks]]''<br />
|Saverio<br />
|-<br />
|Mar 20<br />
|[http://www.seas.upenn.edu/directory/profile.php?ID=3 Paulo Arratia] (U Penn)<br />
|''[[Applied/ACMS/absS15#Paulo Arratia (U Penn)|Pulling & pushing in complex fluids]]''<br />
|Saverio<br />
|-<br />
|''Wed. Mar 25'', '''VV B321'''<br />
|[http://www.cc.ac.cn/staff/tzhou.html Tao Zhou] (Chinese Academy of Sciences)<br />
|''[[Applied/ACMS/absS15#Tao Zhou (Chinese Academy of Sciences)|The Christoffel function weighted least-squares for stochastic<br />
collocation approximations: applications to Uncertainty Quantification]]''<br />
|Shi Jin<br />
|-<br />
|Apr 3<br />
|<br />
|Spring break<br />
|<br />
|-<br />
|''Wed. Apr 8'', '''VV B321'''<br />
|[http://personal.maths.surrey.ac.uk/st/bc0012/ Bin Cheng] (University of Surrey)<br />
|''[[Applied/ACMS/absS15#Bin Cheng (University of Surrey)|Error estimates and 2nd order corrections to reduced fluid models]]''<br />
|Shi Jin<br />
|<br />
|-<br />
|Apr 10<br />
|[http://banajim.myweb.port.ac.uk/ Murad Banaji] (University of Portsmouth)<br />
|''[[Applied/ACMS/absS15#Murad Banaji (University of Portsmouth)| Nonexpansivity in chemical reaction networks]]''<br />
|Craciun<br />
|<br />
|-<br />
|''Mon. Apr 13'', '''VV B321'''<br />
|[http://www.tcs.tifr.res.in/~manoj// Manoj Gopalkrishnan] (Tata Institute Mumbai)<br />
|''[[Applied/ACMS/absS15#Manoj Gopalkrishnan (Tata Institute Mumbai)| Autocatalysis in reaction networks]]''<br />
|Anderson and Craciun<br />
|<br />
|-<br />
|Apr 17<br />
|[http://pages.cs.wisc.edu/~swright/ Stephen Wright] (UW)<br />
|''[[Applied/ACMS/absS15#Stephen Wright (UW)|The revival of coordinate descent methods]]''<br />
|Saverio<br />
|-<br />
|Apr 24<br />
|[https://vivo.brown.edu/display/tpowers Thomas Powers] (Brown)<br />
|''[[Applied/ACMS/absS15#Thomas Powers (Brown)|TBA]]''<br />
|Saverio<br />
|-<br />
|May 1<br />
|[http://www.marquette.edu/mscs/facstaff-spiller.shtml Elaine Spiller] (Marquette)<br />
|''[[Applied/ACMS/absS15#Elaine Spiller (Marquette)|TBA]]''<br />
|Budisic<br />
|}<br />
<br />
<br><br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS15&diff=9638Applied/ACMS/absS152015-04-10T21:52:09Z<p>Craciun: /* Manoj Gopalkrishnan (Tata Institute Mumbai) */</p>
<hr />
<div>= ACMS Abstracts: Spring 2015 =<br />
<br />
=== Irene Kyza (U Dundee) ===<br />
<br />
''Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control''<br />
<br />
We discuss recent results on the a posteriori error control and adaptivity for an evolution semilinear convection-diffusion model problem with possible blowup in finite time. This belongs to the broad class of partial differential equations describing e.g., tumor growth,chemotaxis and cell modelling. In particular, we derive a posteriori error estimates that are conditional (estimates which are valid under conditions of a posteriori type) for an interior penalty discontinuous Galerkin (dG) implicit-explicit (IMEX) method using a continuation argument. Compared to a previous work, the obtained conditions are more localised and allow the efficient error control near the blowup time. Utilising the conditional a posteriori estimator we are able to propose an adaptive algorithm that appears to perform satisfactorily. In particular, it leads to good approximation of the blowup time and of the exact solution close to the blowup. Numerical experiments illustrate and complement our theoretical results. This is joint work with A. Cangiani, E.H. Georgoulis, and S. Metcalfe from the University of Leicester.<br />
<br />
=== Daniel Vimont (UW) ===<br />
<br />
''Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events''<br />
<br />
Research on the structure and evolution of individual El Niño / Southern Oscillation (ENSO) events has identified two categories of ENSO event characteristics that can be defined by maximum equatorial SST anomalies centered in the Central Pacific (around the dateline to 150 deg. W; CP events) or in the Eastern Pacific (east of about 150 deg. W; EP events). The distinction between these two events is not just academic: both types of event evolve differently, implying different predictability; the events tend to have different maximum amplitude; and the global teleconnection differs between each type of event. <br />
<br />
In this presentation I will (i) describe the Linear Inverse Modeling (LIM) technique, (ii) apply LIM to determine an empirical dynamical operator that governs the evolution of tropical Pacific climate variability, (iii) define norms under which initial conditions can be derived that optimally lead to growth of CP or EP ENSO events, and (iv) identify patterns of stochastic forcing that are responsible for exciting each type of event.<br />
<br />
=== Saverio Spagnolie (UW) ===<br />
<br />
''Sedimentation in viscous fluids: flexible filaments and boundary effects''<br />
<br />
The deformation and transport of elastic filaments in viscous fluids play central roles in many biological and technological processes. Compared with the well-studied case of sedimenting rigid rods, the introduction of filament compliance may cause a significant alteration in the long-time sedimentation orientation and filament geometry. In the weakly flexible regime, a multiple-scale asymptotic expansion is used to obtain expressions for filament translations, rotations and shapes which match excellently with full numerical simulations. In the highly flexible regime we show that a filament sedimenting along its long axis is susceptible to a buckling instability. Embedding the analytical results for a single filament into a mean-field theory, we show how flexibility affects a well established concentration instability in a sedimenting suspension. <br />
<br />
Another problem of classical interest in fluid mechanics involves the sedimentation of a rigid particle near a wall, but most studies have been numerical or experimental in nature. We have derived ordinary differential equations describing the sedimentation of arbitrarily oriented prolate and oblate spheroids near a vertical or inclined plane wall which may be solved analytically for many important special cases. Full trajectories are predicted which compare favorably with complete numerical simulations performed using a novel double layer boundary integral formulation, a Method of Stresslet Images. Several trajectory-types emerge, termed tumbling, glancing, reversing, and sliding, along with their fully three-dimensional analogues.<br />
<br />
=== Jonathan Freund (UIUC) ===<br />
<br />
''Adjoint-based optimization for understanding and reducing flow noise''<br />
<br />
Advanced simulation tools, particularly large-eddy simulation techniques, are becoming capable of making quality predictions of jet noise for realistic nozzle geometries and at engineering relevant flow conditions. Increasing computer resources will be a key factor in improving these predictions still further. Quality prediction, however, is only a necessary condition for the use of such simulations in design optimization. Predictions do not of themselves lead to quieter designs. They must be interpreted or harnessed in some way that leads to design improvements. As yet, such simulations have not yielded any simplifying principals that offer general design guidance. The turbulence mechanisms leading to jet noise remain poorly described in their complexity. In this light, we have implemented and demonstrated an aeroacoustic adjoint-based optimization technique that automatically calculates gradients that point the direction in which to adjust controls in order to improve designs. This is done with only a single flow solutions and a solution of an adjoint system, which is solved at computational cost comparable to that for the flow. Optimization requires iterations, but having the gradient information provided via the adjoint accelerates convergence in a manner that is insensitive to the number of parameters to be optimized. The talk will review the formulation of the adjoint of the compressible flow equations for optimizing noise-reducing controls and present examples of its use. We will particularly focus on some mechanisms of flow noise that have been revealed via this approach.<br />
<br />
=== Markos Katsoulakis (U Mass Amherst) ===<br />
<br />
''Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics''<br />
<br />
In this talk we discuss path-space information theory-based sensitivity analysis and parameter identification methods for complex high-dimensional dynamics, as well as information-theoretic tools for parameterized coarse-graining of non-equilibrium extended systems. Furthermore, we establish their connections with goal-oriented methods in terms of new, sharp, uncertainty quantification inequalities. The combination of proposed methodologies is capable to (a) handle molecular-level models with a very large number of parameters, (b) address and mitigate the high-variance in statistical estimators, e.g. for sensitivity analysis, in spatially distributed <br />
<br />
Kinetic Monte Carlo (KMC), (c) tackle non-equilibrium processes, typically associated with coupled physicochemical mechanisms, boundary conditions, etc. (such as reaction-diffusion systems), and where even steady states are unknown altogether, e.g. do not have a Gibbs structure. Finally, the path-wise information theory tools, (d) yield a surprisingly simple, tractable and easy-to-implement approach to quantify and rank parameter sensitivities, as well as (e) provide reliable molecular model parameterizations for coarse-grained molecular systems and their dynamics, based on fine-scale data and rational model selection methods through suitable path-space (dynamics-based) information criteria. The proposed methods are tested against a wide range of high-dimensional stochastic processes, ranging from complex biochemical reaction networks with hundreds of parameters, to spatially extended Kinetic Monte Carlo models in catalysis and Langevin dynamics of interacting molecules with internal degrees of freedom.<br />
<br />
=== Frederic Coquel (Ecole Polytechnique Paris) ===<br />
<br />
''Jin and Xin's Relaxation Solvers with Defect Measure Corrections''<br />
<br />
We present a class of finite volume methods for approximating entropy weak solutions of non-linear hyperbolic PDEs. The main motivation is to resolve discontinuities as well as Glimm's scheme, but without the need for solving Riemann problems exactly. The sharp capture of discontinuities is known to be mandatory in situations where discontinuities are sensitive to viscous perturbations while exact Riemann solutions may not be available (typically in phase transition problems). More generally, sharp capture also prevent discrete shock proles from exhibiting over and undershoots, which is decisive in a many applications (in combustion for instance). We propose to replace exact Riemann solutions by self-similar solutions conveniently derived from the Jin-Xin's relaxation framework. In the limit of a vanishing relaxation time, the relaxation source term exhibits Dirac measures concentrated on the discontinuities. We show how to handle those so-called defect measures in order to exactly capture propagating shock solutions while achieving computational efficiencies. The lecture will essential focus on the convergence analysis in the scalar setting. A special attention is paid to the consistency of the proposed correction with respect to the entropy condition. We prove the convergence of the method to the unique Kruvkov's solution.<br />
<br />
=== Lisa Fauci (Tulane) ===<br />
<br />
''Flagellar motility: negotiating sticky elastic bonds and viscoelastic networks''<br />
<br />
We will discuss a Stokes fluid model that incorporates forces due to elastic structures in the fluid environment of the actuated flagellum. We will present recent computational investigations of hyperactivated sperm detachment from oviductal epithelium as well as swimming through viscoelastic networks. <br />
<br />
=== Paulo Arratia (U Penn) ===<br />
<br />
''Pulling and pushing in complex fluids''<br />
<br />
Many microorganisms evolve in media that contain (bio)-polymers and/or solids; examples include cervical mucus, intestinal fluid, wet soil, and tissues. These so-called complex fluids often exhibit non-Newtonian rheological behavior such as shear-thinning viscosity and elasticity. In this talk, I will discuss recent experiments on the effects of fluid elasticity on the swimming behavior of microorganisms. Two main microorganisms are used, the green algae C. reinhardtii (a puller-type swimmer) and the bacterium E. coli (a pusher-type swimmer). For the case of pullers (C. reinhardtii), we find that fluid elasticity hinders the cell’s overall swimming speed but leads to an increase in the cell’s flagellum beating frequency. The beating kinematics and flagellum waveforms are also significantly modified by fluid elasticity. For the case of pushers (E. coli), the presence of even small amount of polymers in the medium suppresses the bacteria run-and-tumble mechanism. The bacteria spend more time in ballistic mode and swim faster as well. Single molecule experiments using fluorescently labeled DNA show that the flow fields generated by E. coli are able to stretch initially coiled polymer molecules and thus induce elastic stresses in fluid. These results demonstrate the intimate link between swimming kinematics and fluid rheology and that one can control the spreading and motility of microorganisms by tuning fluid properties.<br />
<br />
=== Tao Zhou (Chinese Academy of Sciences) ===<br />
<br />
''The Christoffel function weighted least-squares for stochastic collocation approximations: applications to Uncertainty Quantification''<br />
<br />
We shall consider the multivariate stochastic collocation methods on unstructured grids. The motivation for such a study is the applications in parametric Uncertainty Quantification (UQ). We will first give a general framework of stochastic collocation methods, which include approaches such as compressed sensing, least-squares, and interpolation. Particular attention will be then given to the least-squares approach, and we will review recent progresses in this topic.<br />
<br />
=== Bin Cheng (University of Surrey) ===<br />
<br />
'Error estimates and 2nd order corrections to reduced fluid models''<br />
<br />
In this PDE analysis work, I will discuss the application of time-averaging in getting rigorous error estimates of some reduced fluid models, including the incompressible approximation and quasi-geostrophic approximation. The spatial boundary can be present as a non-penetrable solid wall. I will show a somewhat surprising result on the epsilon^2 accuracy of incompressible approximation of Euler equations, thanks to several decoupling properties.<br />
<br />
=== Murad Banaji (University of Portsmouth) ===<br />
<br />
''Nonexpansivity in chemical reaction networks''<br />
<br />
This work is motivated by the observation that quite often systems of differential equations describing chemical reaction networks (CRNs) display simple global behaviour such as convergence of all orbits to a unique equilibrium under only weak and physically reasonable assumptions on the reaction rates (kinetics). We are led to wonder if the structure of a CRN may sometimes force some distance between solutions to decrease (or at least not increase) with time. If so, how can we find this nonincreasing quantity? We explore different ways in which CRNs can define nonexpansive semiflows (recall that a semiflow <math>(\phi_t)_{t \geq 0}</math> on some Banach space <math>(X, |\cdot|)</math> is nonexpansive if <math>|\phi_t(x)-\phi_t(y)| \leq |x-y|</math> for all <math>x,y \in X</math> and all <math>t \geq 0</math>). It turns out that in CRNs the natural evolution of chemical concentrations may be nonexpansive; or a nonexpansive semiflow may be obtained from the evolution of the so-called "extents" of reactions. In both cases we may be able to draw global conclusions about convergence of chemical concentrations. In each case the challenge is to find the correct norm to get nonexpansivity for arbitrary kinetics. To construct such norms and show nonexpansivity we appeal to the theory of monotone dynamical systems. Families of CRNs which can be analysed in this way are presented; however characterising fully the class of CRNs to which this theory applies remains an open - and undoubtedly difficult - task.<br />
<br />
This is joint work with Bas Lemmens (University of Kent) and Pete Donnell (University of Portsmouth).<br />
<br />
<br />
=== Manoj Gopalkrishnan (Tata Institute Mumbai) ===<br />
<br />
''Autocatalysis in Reaction Networks"<br />
<br />
Abstract: The notion of "critical siphon" has been studied in reaction network theory in the context of the persistence question. We explore the combinatorics of critical siphons. We introduce the notions of "drainable" and "self-replicable" (or autocatalytic) siphons. We show that: every minimal critical siphon is either drainable or self-replicable; reaction networks without drainable siphons are persistent; and non-autocatalytic weakly-reversible networks are persistent. This result generalizes previous results for catalytic and atomic reaction networks. The proof is combinatorial in nature<br />
<br />
Reference: http://arxiv.org/abs/1309.3957<br />
<br />
=== Stephen Wright (UW) ===<br />
<br />
''The revival of coordinate descent methods''<br />
<br />
The approach of minimizing a function by successively fixing most of its variables and minimizing with respect to the others dates back many years, and has been applied in an enormous range of applications. Until recently, however, the approach did not command much respect among optimization researchers; only a few prominent individuals took it seriously. Recent years have seen an explosion in applications, particularly in data analysis, which has driven a new wave of research into variants of coordinate descent and their convergence properties. Such aspects as randomization in the choice of variants to fix and relax, acceleration methods, extension to regularized objectives, and parallel implementation have commanded a good deal of attention during the past five years. In this lecture, I will survey these recent developments, then focus on recent work on asynchronous parallel implementations for multicore computers. An analysis of the properties of the latter algorithms shows that near-linear speedup can be expected, up to a number of processors that depends on the coupling between the variables.<br />
<br />
This talk covers joint work with Ji Liu and other colleagues.<br />
<br />
=== Elaine Spiller (Marquette) ===<br />
<br />
TBA</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=9588Applied/ACMS2015-04-02T19:37:26Z<p>Craciun: /* Spring 2015 Semester */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://lists.math.wisc.edu/listinfo/acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2015 Semester ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Jan 23<br />
|[http://www.maths.dundee.ac.uk/ikyza/IreneKyza/ Irene Kyza] (U Dundee)<br />
|''[[Applied/ACMS/absS15#Irene Kyza (U Dundee)|Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control]]''<br />
|Shi Jin <br />
|-<br />
|Jan 30<br />
|[http://www.aos.wisc.edu/~dvimont/ Daniel Vimont] (UW)<br />
|''[[Applied/ACMS/absS15#Daniel Vimont (UW)|Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events]]''<br />
|Sam, Saverio<br />
|<br />
|-<br />
|Feb 13<br />
|[http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] (UW)<br />
|''[[Applied/ACMS/absS15#Saverio Spagnolie (UW)|Sedimentation in viscous fluids: flexible filaments and boundary effects]]''<br />
|<br />
|-<br />
|Feb 20<br />
|[http://jbfreund.mechse.illinois.edu/ Jonathan Freund] (U Illinois)<br />
|''[[Applied/ACMS/absS15#Jonathan Freund (UIUC)|Adjoint-based optimization for understanding and reducing flow noise]]''<br />
|Saverio<br />
|-<br />
|Feb 27<br />
|[http://people.math.umass.edu/~markos/ Markos Katsoulakis] (U Mass Amherst)<br />
|''[[Applied/ACMS/absS15#Markos Katsoulakis (U Mass Amherst)|Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics]]''<br />
|Shi Jin<br />
|-<br />
|Mar 6<br />
|[https://www.ljll.math.upmc.fr/~coquel/node2.html Frederic Coquel] (Ecole Polytechnique Paris)<br />
|''[[Applied/ACMS/absS15#Frederic Coquel (Ecole Polytechnique Paris)|Jin and Xin's Relaxation Framework with Defect Measure Corrections]]''<br />
|Shi Jin<br />
|-<br />
|Mar 13<br />
|[http://dauns.math.tulane.edu/~ljf/ Lisa Fauci] (Tulane)<br />
|''[[Applied/ACMS/absS15#Lisa Fauci (Tulane)|Flagellar motility: negotiating sticky elastic bonds and viscoelastic networks]]''<br />
|Saverio<br />
|-<br />
|Mar 20<br />
|[http://www.seas.upenn.edu/directory/profile.php?ID=3 Paulo Arratia] (U Penn)<br />
|''[[Applied/ACMS/absS15#Paulo Arratia (U Penn)|Pulling & pushing in complex fluids]]''<br />
|Saverio<br />
|-<br />
|''Wed. Mar 25'', '''VV B321'''<br />
|[http://www.cc.ac.cn/staff/tzhou.html Tao Zhou] (Chinese Academy of Sciences)<br />
|''[[Applied/ACMS/absS15#Tao Zhou (Chinese Academy of Sciences)|The Christoffel function weighted least-squares for stochastic<br />
collocation approximations: applications to Uncertainty Quantification]]''<br />
|Shi Jin<br />
|-<br />
|Apr 3<br />
|<br />
|Spring break<br />
|<br />
|-<br />
|''Wed. Apr 8'', '''VV B321'''<br />
|[http://personal.maths.surrey.ac.uk/st/bc0012/ Bin Cheng] (University of Surrey)<br />
|''[[Applied/ACMS/absS15#Bin Cheng (University of Surrey)|Error estimates and 2nd order corrections to reduced fluid models]]''<br />
|Shi Jin<br />
|<br />
|-<br />
|Apr 10<br />
|[http://banajim.myweb.port.ac.uk/ Murad Banaji] (University of Portsmouth)<br />
|''[[Applied/ACMS/absS15#Murad Banaji (University of Portsmouth)| Nonexpansivity in chemical reaction networks]]''<br />
|Craciun<br />
|<br />
|-<br />
|''Mon. Apr 13'', '''room TBA'''<br />
|[http://www.tcs.tifr.res.in/~manoj// Manoj Gopalkrishnan] (Tata Institute Mumbai)<br />
|''[[Applied/ACMS/absS15#Manoj Gopalkrishnan (Tata Institute Mumbai)| TBA]]''<br />
|Anderson and Craciun<br />
|<br />
|-<br />
|Apr 17<br />
|[http://pages.cs.wisc.edu/~swright/ Stephen Wright] (UW)<br />
|''[[Applied/ACMS/absS15#Stephen Wright (UW)|The revival of coordinate descent methods]]''<br />
|Saverio<br />
|-<br />
|Apr 24<br />
|[https://vivo.brown.edu/display/tpowers Thomas Powers] (Brown)<br />
|''[[Applied/ACMS/absS15#Thomas Powers (Brown)|TBA]]''<br />
|Saverio<br />
|-<br />
|May 1<br />
|[http://www.marquette.edu/mscs/facstaff-spiller.shtml Elaine Spiller] (Marquette)<br />
|''[[Applied/ACMS/absS15#Elaine Spiller (Marquette)|TBA]]''<br />
|Budisic<br />
|}<br />
<br />
<br><br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=9587Applied/ACMS2015-04-02T19:31:08Z<p>Craciun: /* Spring 2015 Semester */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://lists.math.wisc.edu/listinfo/acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2015 Semester ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Jan 23<br />
|[http://www.maths.dundee.ac.uk/ikyza/IreneKyza/ Irene Kyza] (U Dundee)<br />
|''[[Applied/ACMS/absS15#Irene Kyza (U Dundee)|Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control]]''<br />
|Shi Jin <br />
|-<br />
|Jan 30<br />
|[http://www.aos.wisc.edu/~dvimont/ Daniel Vimont] (UW)<br />
|''[[Applied/ACMS/absS15#Daniel Vimont (UW)|Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events]]''<br />
|Sam, Saverio<br />
|<br />
|-<br />
|Feb 13<br />
|[http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] (UW)<br />
|''[[Applied/ACMS/absS15#Saverio Spagnolie (UW)|Sedimentation in viscous fluids: flexible filaments and boundary effects]]''<br />
|<br />
|-<br />
|Feb 20<br />
|[http://jbfreund.mechse.illinois.edu/ Jonathan Freund] (U Illinois)<br />
|''[[Applied/ACMS/absS15#Jonathan Freund (UIUC)|Adjoint-based optimization for understanding and reducing flow noise]]''<br />
|Saverio<br />
|-<br />
|Feb 27<br />
|[http://people.math.umass.edu/~markos/ Markos Katsoulakis] (U Mass Amherst)<br />
|''[[Applied/ACMS/absS15#Markos Katsoulakis (U Mass Amherst)|Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics]]''<br />
|Shi Jin<br />
|-<br />
|Mar 6<br />
|[https://www.ljll.math.upmc.fr/~coquel/node2.html Frederic Coquel] (Ecole Polytechnique Paris)<br />
|''[[Applied/ACMS/absS15#Frederic Coquel (Ecole Polytechnique Paris)|Jin and Xin's Relaxation Framework with Defect Measure Corrections]]''<br />
|Shi Jin<br />
|-<br />
|Mar 13<br />
|[http://dauns.math.tulane.edu/~ljf/ Lisa Fauci] (Tulane)<br />
|''[[Applied/ACMS/absS15#Lisa Fauci (Tulane)|Flagellar motility: negotiating sticky elastic bonds and viscoelastic networks]]''<br />
|Saverio<br />
|-<br />
|Mar 20<br />
|[http://www.seas.upenn.edu/directory/profile.php?ID=3 Paulo Arratia] (U Penn)<br />
|''[[Applied/ACMS/absS15#Paulo Arratia (U Penn)|Pulling & pushing in complex fluids]]''<br />
|Saverio<br />
|-<br />
|''Wed. Mar 25'', '''VV B321'''<br />
|[http://www.cc.ac.cn/staff/tzhou.html Tao Zhou] (Chinese Academy of Sciences)<br />
|''[[Applied/ACMS/absS15#Tao Zhou (Chinese Academy of Sciences)|The Christoffel function weighted least-squares for stochastic<br />
collocation approximations: applications to Uncertainty Quantification]]''<br />
|Shi Jin<br />
|-<br />
|Apr 3<br />
|<br />
|Spring break<br />
|<br />
|-<br />
|''Wed. Apr 8'', '''VV B321'''<br />
|[http://personal.maths.surrey.ac.uk/st/bc0012/ Bin Cheng] (University of Surrey)<br />
|''[[Applied/ACMS/absS15#Bin Cheng (University of Surrey)|Error estimates and 2nd order corrections to reduced fluid models]]''<br />
|Shi Jin<br />
|<br />
|-<br />
|Apr 10<br />
|[http://banajim.myweb.port.ac.uk/ Murad Banaji] (University of Portsmouth)<br />
|''[[Applied/ACMS/absS15#Murad Banaji (University of Portsmouth)| Nonexpansivity in chemical reaction networks]]''<br />
|Craciun<br />
|<br />
|-<br />
|''Mon. Apr. 13'', '''room TBA'''<br />
|[http://www.tcs.tifr.res.in/~manoj// Manoj Gopalkrishnan] (Tata Institute Mumbai)<br />
|''[[Applied/ACMS/absS15#Manoj Gopalkrishnan (Tata Institute Mumbai)| TBA]]''<br />
|Anderson and Craciun<br />
|<br />
|-<br />
|Apr 17<br />
|[http://pages.cs.wisc.edu/~swright/ Stephen Wright] (UW)<br />
|''[[Applied/ACMS/absS15#Stephen Wright (UW)|The revival of coordinate descent methods]]''<br />
|Saverio<br />
|-<br />
|Apr 24<br />
|[https://vivo.brown.edu/display/tpowers Thomas Powers] (Brown)<br />
|''[[Applied/ACMS/absS15#Thomas Powers (Brown)|TBA]]''<br />
|Saverio<br />
|-<br />
|May 1<br />
|[http://www.marquette.edu/mscs/facstaff-spiller.shtml Elaine Spiller] (Marquette)<br />
|''[[Applied/ACMS/absS15#Elaine Spiller (Marquette)|TBA]]''<br />
|Budisic<br />
|}<br />
<br />
<br><br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS15&diff=9586Applied/ACMS/absS152015-04-02T19:29:11Z<p>Craciun: /* ACMS Abstracts: Spring 2015 */</p>
<hr />
<div>= ACMS Abstracts: Spring 2015 =<br />
<br />
=== Irene Kyza (U Dundee) ===<br />
<br />
''Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control''<br />
<br />
We discuss recent results on the a posteriori error control and adaptivity for an evolution semilinear convection-diffusion model problem with possible blowup in finite time. This belongs to the broad class of partial differential equations describing e.g., tumor growth,chemotaxis and cell modelling. In particular, we derive a posteriori error estimates that are conditional (estimates which are valid under conditions of a posteriori type) for an interior penalty discontinuous Galerkin (dG) implicit-explicit (IMEX) method using a continuation argument. Compared to a previous work, the obtained conditions are more localised and allow the efficient error control near the blowup time. Utilising the conditional a posteriori estimator we are able to propose an adaptive algorithm that appears to perform satisfactorily. In particular, it leads to good approximation of the blowup time and of the exact solution close to the blowup. Numerical experiments illustrate and complement our theoretical results. This is joint work with A. Cangiani, E.H. Georgoulis, and S. Metcalfe from the University of Leicester.<br />
<br />
=== Daniel Vimont (UW) ===<br />
<br />
''Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events''<br />
<br />
Research on the structure and evolution of individual El Niño / Southern Oscillation (ENSO) events has identified two categories of ENSO event characteristics that can be defined by maximum equatorial SST anomalies centered in the Central Pacific (around the dateline to 150 deg. W; CP events) or in the Eastern Pacific (east of about 150 deg. W; EP events). The distinction between these two events is not just academic: both types of event evolve differently, implying different predictability; the events tend to have different maximum amplitude; and the global teleconnection differs between each type of event. <br />
<br />
In this presentation I will (i) describe the Linear Inverse Modeling (LIM) technique, (ii) apply LIM to determine an empirical dynamical operator that governs the evolution of tropical Pacific climate variability, (iii) define norms under which initial conditions can be derived that optimally lead to growth of CP or EP ENSO events, and (iv) identify patterns of stochastic forcing that are responsible for exciting each type of event.<br />
<br />
=== Saverio Spagnolie (UW) ===<br />
<br />
''Sedimentation in viscous fluids: flexible filaments and boundary effects''<br />
<br />
The deformation and transport of elastic filaments in viscous fluids play central roles in many biological and technological processes. Compared with the well-studied case of sedimenting rigid rods, the introduction of filament compliance may cause a significant alteration in the long-time sedimentation orientation and filament geometry. In the weakly flexible regime, a multiple-scale asymptotic expansion is used to obtain expressions for filament translations, rotations and shapes which match excellently with full numerical simulations. In the highly flexible regime we show that a filament sedimenting along its long axis is susceptible to a buckling instability. Embedding the analytical results for a single filament into a mean-field theory, we show how flexibility affects a well established concentration instability in a sedimenting suspension. <br />
<br />
Another problem of classical interest in fluid mechanics involves the sedimentation of a rigid particle near a wall, but most studies have been numerical or experimental in nature. We have derived ordinary differential equations describing the sedimentation of arbitrarily oriented prolate and oblate spheroids near a vertical or inclined plane wall which may be solved analytically for many important special cases. Full trajectories are predicted which compare favorably with complete numerical simulations performed using a novel double layer boundary integral formulation, a Method of Stresslet Images. Several trajectory-types emerge, termed tumbling, glancing, reversing, and sliding, along with their fully three-dimensional analogues.<br />
<br />
=== Jonathan Freund (UIUC) ===<br />
<br />
''Adjoint-based optimization for understanding and reducing flow noise''<br />
<br />
Advanced simulation tools, particularly large-eddy simulation techniques, are becoming capable of making quality predictions of jet noise for realistic nozzle geometries and at engineering relevant flow conditions. Increasing computer resources will be a key factor in improving these predictions still further. Quality prediction, however, is only a necessary condition for the use of such simulations in design optimization. Predictions do not of themselves lead to quieter designs. They must be interpreted or harnessed in some way that leads to design improvements. As yet, such simulations have not yielded any simplifying principals that offer general design guidance. The turbulence mechanisms leading to jet noise remain poorly described in their complexity. In this light, we have implemented and demonstrated an aeroacoustic adjoint-based optimization technique that automatically calculates gradients that point the direction in which to adjust controls in order to improve designs. This is done with only a single flow solutions and a solution of an adjoint system, which is solved at computational cost comparable to that for the flow. Optimization requires iterations, but having the gradient information provided via the adjoint accelerates convergence in a manner that is insensitive to the number of parameters to be optimized. The talk will review the formulation of the adjoint of the compressible flow equations for optimizing noise-reducing controls and present examples of its use. We will particularly focus on some mechanisms of flow noise that have been revealed via this approach.<br />
<br />
=== Markos Katsoulakis (U Mass Amherst) ===<br />
<br />
''Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics''<br />
<br />
In this talk we discuss path-space information theory-based sensitivity analysis and parameter identification methods for complex high-dimensional dynamics, as well as information-theoretic tools for parameterized coarse-graining of non-equilibrium extended systems. Furthermore, we establish their connections with goal-oriented methods in terms of new, sharp, uncertainty quantification inequalities. The combination of proposed methodologies is capable to (a) handle molecular-level models with a very large number of parameters, (b) address and mitigate the high-variance in statistical estimators, e.g. for sensitivity analysis, in spatially distributed <br />
<br />
Kinetic Monte Carlo (KMC), (c) tackle non-equilibrium processes, typically associated with coupled physicochemical mechanisms, boundary conditions, etc. (such as reaction-diffusion systems), and where even steady states are unknown altogether, e.g. do not have a Gibbs structure. Finally, the path-wise information theory tools, (d) yield a surprisingly simple, tractable and easy-to-implement approach to quantify and rank parameter sensitivities, as well as (e) provide reliable molecular model parameterizations for coarse-grained molecular systems and their dynamics, based on fine-scale data and rational model selection methods through suitable path-space (dynamics-based) information criteria. The proposed methods are tested against a wide range of high-dimensional stochastic processes, ranging from complex biochemical reaction networks with hundreds of parameters, to spatially extended Kinetic Monte Carlo models in catalysis and Langevin dynamics of interacting molecules with internal degrees of freedom.<br />
<br />
=== Frederic Coquel (Ecole Polytechnique Paris) ===<br />
<br />
''Jin and Xin's Relaxation Solvers with Defect Measure Corrections''<br />
<br />
We present a class of finite volume methods for approximating entropy weak solutions of non-linear hyperbolic PDEs. The main motivation is to resolve discontinuities as well as Glimm's scheme, but without the need for solving Riemann problems exactly. The sharp capture of discontinuities is known to be mandatory in situations where discontinuities are sensitive to viscous perturbations while exact Riemann solutions may not be available (typically in phase transition problems). More generally, sharp capture also prevent discrete shock proles from exhibiting over and undershoots, which is decisive in a many applications (in combustion for instance). We propose to replace exact Riemann solutions by self-similar solutions conveniently derived from the Jin-Xin's relaxation framework. In the limit of a vanishing relaxation time, the relaxation source term exhibits Dirac measures concentrated on the discontinuities. We show how to handle those so-called defect measures in order to exactly capture propagating shock solutions while achieving computational efficiencies. The lecture will essential focus on the convergence analysis in the scalar setting. A special attention is paid to the consistency of the proposed correction with respect to the entropy condition. We prove the convergence of the method to the unique Kruvkov's solution.<br />
<br />
=== Lisa Fauci (Tulane) ===<br />
<br />
''Flagellar motility: negotiating sticky elastic bonds and viscoelastic networks''<br />
<br />
We will discuss a Stokes fluid model that incorporates forces due to elastic structures in the fluid environment of the actuated flagellum. We will present recent computational investigations of hyperactivated sperm detachment from oviductal epithelium as well as swimming through viscoelastic networks. <br />
<br />
=== Paulo Arratia (U Penn) ===<br />
<br />
''Pulling and pushing in complex fluids''<br />
<br />
Many microorganisms evolve in media that contain (bio)-polymers and/or solids; examples include cervical mucus, intestinal fluid, wet soil, and tissues. These so-called complex fluids often exhibit non-Newtonian rheological behavior such as shear-thinning viscosity and elasticity. In this talk, I will discuss recent experiments on the effects of fluid elasticity on the swimming behavior of microorganisms. Two main microorganisms are used, the green algae C. reinhardtii (a puller-type swimmer) and the bacterium E. coli (a pusher-type swimmer). For the case of pullers (C. reinhardtii), we find that fluid elasticity hinders the cell’s overall swimming speed but leads to an increase in the cell’s flagellum beating frequency. The beating kinematics and flagellum waveforms are also significantly modified by fluid elasticity. For the case of pushers (E. coli), the presence of even small amount of polymers in the medium suppresses the bacteria run-and-tumble mechanism. The bacteria spend more time in ballistic mode and swim faster as well. Single molecule experiments using fluorescently labeled DNA show that the flow fields generated by E. coli are able to stretch initially coiled polymer molecules and thus induce elastic stresses in fluid. These results demonstrate the intimate link between swimming kinematics and fluid rheology and that one can control the spreading and motility of microorganisms by tuning fluid properties.<br />
<br />
=== Tao Zhou (Chinese Academy of Sciences) ===<br />
<br />
''The Christoffel function weighted least-squares for stochastic collocation approximations: applications to Uncertainty Quantification''<br />
<br />
We shall consider the multivariate stochastic collocation methods on unstructured grids. The motivation for such a study is the applications in parametric Uncertainty Quantification (UQ). We will first give a general framework of stochastic collocation methods, which include approaches such as compressed sensing, least-squares, and interpolation. Particular attention will be then given to the least-squares approach, and we will review recent progresses in this topic.<br />
<br />
=== Bin Cheng (University of Surrey) ===<br />
<br />
'Error estimates and 2nd order corrections to reduced fluid models''<br />
<br />
In this PDE analysis work, I will discuss the application of time-averaging in getting rigorous error estimates of some reduced fluid models, including the incompressible approximation and quasi-geostrophic approximation. The spatial boundary can be present as a non-penetrable solid wall. I will show a somewhat surprising result on the epsilon^2 accuracy of incompressible approximation of Euler equations, thanks to several decoupling properties.<br />
<br />
=== Murad Banaji (University of Portsmouth) ===<br />
<br />
''Nonexpansivity in chemical reaction networks''<br />
<br />
This work is motivated by the observation that quite often systems of differential equations describing chemical reaction networks (CRNs) display simple global behaviour such as convergence of all orbits to a unique equilibrium under only weak and physically reasonable assumptions on the reaction rates (kinetics). We are led to wonder if the structure of a CRN may sometimes force some distance between solutions to decrease (or at least not increase) with time. If so, how can we find this nonincreasing quantity? We explore different ways in which CRNs can define nonexpansive semiflows (recall that a semiflow <math>(\phi_t)_{t \geq 0}</math> on some Banach space <math>(X, |\cdot|)</math> is nonexpansive if <math>|\phi_t(x)-\phi_t(y)| \leq |x-y|</math> for all <math>x,y \in X</math> and all <math>t \geq 0</math>). It turns out that in CRNs the natural evolution of chemical concentrations may be nonexpansive; or a nonexpansive semiflow may be obtained from the evolution of the so-called "extents" of reactions. In both cases we may be able to draw global conclusions about convergence of chemical concentrations. In each case the challenge is to find the correct norm to get nonexpansivity for arbitrary kinetics. To construct such norms and show nonexpansivity we appeal to the theory of monotone dynamical systems. Families of CRNs which can be analysed in this way are presented; however characterising fully the class of CRNs to which this theory applies remains an open - and undoubtedly difficult - task.<br />
<br />
This is joint work with Bas Lemmens (University of Kent) and Pete Donnell (University of Portsmouth).<br />
<br />
<br />
=== Manoj Gopalkrishnan (Tata Institute Mumbai) ===<br />
<br />
''TBA''<br />
<br />
<br />
<br />
=== Stephen Wright (UW) ===<br />
<br />
''The revival of coordinate descent methods''<br />
<br />
The approach of minimizing a function by successively fixing most of its variables and minimizing with respect to the others dates back many years, and has been applied in an enormous range of applications. Until recently, however, the approach did not command much respect among optimization researchers; only a few prominent individuals took it seriously. Recent years have seen an explosion in applications, particularly in data analysis, which has driven a new wave of research into variants of coordinate descent and their convergence properties. Such aspects as randomization in the choice of variants to fix and relax, acceleration methods, extension to regularized objectives, and parallel implementation have commanded a good deal of attention during the past five years. In this lecture, I will survey these recent developments, then focus on recent work on asynchronous parallel implementations for multicore computers. An analysis of the properties of the latter algorithms shows that near-linear speedup can be expected, up to a number of processors that depends on the coupling between the variables.<br />
<br />
This talk covers joint work with Ji Liu and other colleagues.<br />
<br />
=== Elaine Spiller (Marquette) ===<br />
<br />
TBA</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=9585Applied/ACMS2015-04-02T19:25:10Z<p>Craciun: /* Spring 2015 Semester */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://lists.math.wisc.edu/listinfo/acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2015 Semester ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Jan 23<br />
|[http://www.maths.dundee.ac.uk/ikyza/IreneKyza/ Irene Kyza] (U Dundee)<br />
|''[[Applied/ACMS/absS15#Irene Kyza (U Dundee)|Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control]]''<br />
|Shi Jin <br />
|-<br />
|Jan 30<br />
|[http://www.aos.wisc.edu/~dvimont/ Daniel Vimont] (UW)<br />
|''[[Applied/ACMS/absS15#Daniel Vimont (UW)|Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events]]''<br />
|Sam, Saverio<br />
|<br />
|-<br />
|Feb 13<br />
|[http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] (UW)<br />
|''[[Applied/ACMS/absS15#Saverio Spagnolie (UW)|Sedimentation in viscous fluids: flexible filaments and boundary effects]]''<br />
|<br />
|-<br />
|Feb 20<br />
|[http://jbfreund.mechse.illinois.edu/ Jonathan Freund] (U Illinois)<br />
|''[[Applied/ACMS/absS15#Jonathan Freund (UIUC)|Adjoint-based optimization for understanding and reducing flow noise]]''<br />
|Saverio<br />
|-<br />
|Feb 27<br />
|[http://people.math.umass.edu/~markos/ Markos Katsoulakis] (U Mass Amherst)<br />
|''[[Applied/ACMS/absS15#Markos Katsoulakis (U Mass Amherst)|Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics]]''<br />
|Shi Jin<br />
|-<br />
|Mar 6<br />
|[https://www.ljll.math.upmc.fr/~coquel/node2.html Frederic Coquel] (Ecole Polytechnique Paris)<br />
|''[[Applied/ACMS/absS15#Frederic Coquel (Ecole Polytechnique Paris)|Jin and Xin's Relaxation Framework with Defect Measure Corrections]]''<br />
|Shi Jin<br />
|-<br />
|Mar 13<br />
|[http://dauns.math.tulane.edu/~ljf/ Lisa Fauci] (Tulane)<br />
|''[[Applied/ACMS/absS15#Lisa Fauci (Tulane)|Flagellar motility: negotiating sticky elastic bonds and viscoelastic networks]]''<br />
|Saverio<br />
|-<br />
|Mar 20<br />
|[http://www.seas.upenn.edu/directory/profile.php?ID=3 Paulo Arratia] (U Penn)<br />
|''[[Applied/ACMS/absS15#Paulo Arratia (U Penn)|Pulling & pushing in complex fluids]]''<br />
|Saverio<br />
|-<br />
|''Wed. Mar 25'', '''VV B321'''<br />
|[http://www.cc.ac.cn/staff/tzhou.html Tao Zhou] (Chinese Academy of Sciences)<br />
|''[[Applied/ACMS/absS15#Tao Zhou (Chinese Academy of Sciences)|The Christoffel function weighted least-squares for stochastic<br />
collocation approximations: applications to Uncertainty Quantification]]''<br />
|Shi Jin<br />
|-<br />
|Apr 3<br />
|<br />
|Spring break<br />
|<br />
|-<br />
|''Wed. Apr 8'', '''VV B321'''<br />
|[http://personal.maths.surrey.ac.uk/st/bc0012/ Bin Cheng] (University of Surrey)<br />
|''[[Applied/ACMS/absS15#Bin Cheng (University of Surrey)|Error estimates and 2nd order corrections to reduced fluid models]]''<br />
|Shi Jin<br />
|<br />
|-<br />
|Apr 10<br />
|[http://banajim.myweb.port.ac.uk/ Murad Banaji] (University of Portsmouth)<br />
|''[[Applied/ACMS/absS15#Murad Banaji (University of Portsmouth)| Nonexpansivity in chemical reaction networks]]''<br />
|Craciun<br />
|<br />
|-<br />
|Apr 13<br />
|[http://www.tcs.tifr.res.in/~manoj// Manoj Gopalkrishnan] (Tata Institute Mumbai)<br />
|''[[Applied/ACMS/absS15#Manoj Gopalkrishnan (Tata Institute Mumbai)| TBA]]''<br />
|Anderson and Craciun<br />
|<br />
|-<br />
|Apr 17<br />
|[http://pages.cs.wisc.edu/~swright/ Stephen Wright] (UW)<br />
|''[[Applied/ACMS/absS15#Stephen Wright (UW)|The revival of coordinate descent methods]]''<br />
|Saverio<br />
|-<br />
|Apr 24<br />
|[https://vivo.brown.edu/display/tpowers Thomas Powers] (Brown)<br />
|''[[Applied/ACMS/absS15#Thomas Powers (Brown)|TBA]]''<br />
|Saverio<br />
|-<br />
|May 1<br />
|[http://www.marquette.edu/mscs/facstaff-spiller.shtml Elaine Spiller] (Marquette)<br />
|''[[Applied/ACMS/absS15#Elaine Spiller (Marquette)|TBA]]''<br />
|Budisic<br />
|}<br />
<br />
<br><br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS15&diff=9580Applied/ACMS/absS152015-03-31T17:53:57Z<p>Craciun: /* ACMS Abstracts: Spring 2015 */</p>
<hr />
<div>= ACMS Abstracts: Spring 2015 =<br />
<br />
=== Irene Kyza (U Dundee) ===<br />
<br />
''Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control''<br />
<br />
We discuss recent results on the a posteriori error control and adaptivity for an evolution semilinear convection-diffusion model problem with possible blowup in finite time. This belongs to the broad class of partial differential equations describing e.g., tumor growth,chemotaxis and cell modelling. In particular, we derive a posteriori error estimates that are conditional (estimates which are valid under conditions of a posteriori type) for an interior penalty discontinuous Galerkin (dG) implicit-explicit (IMEX) method using a continuation argument. Compared to a previous work, the obtained conditions are more localised and allow the efficient error control near the blowup time. Utilising the conditional a posteriori estimator we are able to propose an adaptive algorithm that appears to perform satisfactorily. In particular, it leads to good approximation of the blowup time and of the exact solution close to the blowup. Numerical experiments illustrate and complement our theoretical results. This is joint work with A. Cangiani, E.H. Georgoulis, and S. Metcalfe from the University of Leicester.<br />
<br />
=== Daniel Vimont (UW) ===<br />
<br />
''Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events''<br />
<br />
Research on the structure and evolution of individual El Niño / Southern Oscillation (ENSO) events has identified two categories of ENSO event characteristics that can be defined by maximum equatorial SST anomalies centered in the Central Pacific (around the dateline to 150 deg. W; CP events) or in the Eastern Pacific (east of about 150 deg. W; EP events). The distinction between these two events is not just academic: both types of event evolve differently, implying different predictability; the events tend to have different maximum amplitude; and the global teleconnection differs between each type of event. <br />
<br />
In this presentation I will (i) describe the Linear Inverse Modeling (LIM) technique, (ii) apply LIM to determine an empirical dynamical operator that governs the evolution of tropical Pacific climate variability, (iii) define norms under which initial conditions can be derived that optimally lead to growth of CP or EP ENSO events, and (iv) identify patterns of stochastic forcing that are responsible for exciting each type of event.<br />
<br />
=== Saverio Spagnolie (UW) ===<br />
<br />
''Sedimentation in viscous fluids: flexible filaments and boundary effects''<br />
<br />
The deformation and transport of elastic filaments in viscous fluids play central roles in many biological and technological processes. Compared with the well-studied case of sedimenting rigid rods, the introduction of filament compliance may cause a significant alteration in the long-time sedimentation orientation and filament geometry. In the weakly flexible regime, a multiple-scale asymptotic expansion is used to obtain expressions for filament translations, rotations and shapes which match excellently with full numerical simulations. In the highly flexible regime we show that a filament sedimenting along its long axis is susceptible to a buckling instability. Embedding the analytical results for a single filament into a mean-field theory, we show how flexibility affects a well established concentration instability in a sedimenting suspension. <br />
<br />
Another problem of classical interest in fluid mechanics involves the sedimentation of a rigid particle near a wall, but most studies have been numerical or experimental in nature. We have derived ordinary differential equations describing the sedimentation of arbitrarily oriented prolate and oblate spheroids near a vertical or inclined plane wall which may be solved analytically for many important special cases. Full trajectories are predicted which compare favorably with complete numerical simulations performed using a novel double layer boundary integral formulation, a Method of Stresslet Images. Several trajectory-types emerge, termed tumbling, glancing, reversing, and sliding, along with their fully three-dimensional analogues.<br />
<br />
=== Jonathan Freund (UIUC) ===<br />
<br />
''Adjoint-based optimization for understanding and reducing flow noise''<br />
<br />
Advanced simulation tools, particularly large-eddy simulation techniques, are becoming capable of making quality predictions of jet noise for realistic nozzle geometries and at engineering relevant flow conditions. Increasing computer resources will be a key factor in improving these predictions still further. Quality prediction, however, is only a necessary condition for the use of such simulations in design optimization. Predictions do not of themselves lead to quieter designs. They must be interpreted or harnessed in some way that leads to design improvements. As yet, such simulations have not yielded any simplifying principals that offer general design guidance. The turbulence mechanisms leading to jet noise remain poorly described in their complexity. In this light, we have implemented and demonstrated an aeroacoustic adjoint-based optimization technique that automatically calculates gradients that point the direction in which to adjust controls in order to improve designs. This is done with only a single flow solutions and a solution of an adjoint system, which is solved at computational cost comparable to that for the flow. Optimization requires iterations, but having the gradient information provided via the adjoint accelerates convergence in a manner that is insensitive to the number of parameters to be optimized. The talk will review the formulation of the adjoint of the compressible flow equations for optimizing noise-reducing controls and present examples of its use. We will particularly focus on some mechanisms of flow noise that have been revealed via this approach.<br />
<br />
=== Markos Katsoulakis (U Mass Amherst) ===<br />
<br />
''Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics''<br />
<br />
In this talk we discuss path-space information theory-based sensitivity analysis and parameter identification methods for complex high-dimensional dynamics, as well as information-theoretic tools for parameterized coarse-graining of non-equilibrium extended systems. Furthermore, we establish their connections with goal-oriented methods in terms of new, sharp, uncertainty quantification inequalities. The combination of proposed methodologies is capable to (a) handle molecular-level models with a very large number of parameters, (b) address and mitigate the high-variance in statistical estimators, e.g. for sensitivity analysis, in spatially distributed <br />
<br />
Kinetic Monte Carlo (KMC), (c) tackle non-equilibrium processes, typically associated with coupled physicochemical mechanisms, boundary conditions, etc. (such as reaction-diffusion systems), and where even steady states are unknown altogether, e.g. do not have a Gibbs structure. Finally, the path-wise information theory tools, (d) yield a surprisingly simple, tractable and easy-to-implement approach to quantify and rank parameter sensitivities, as well as (e) provide reliable molecular model parameterizations for coarse-grained molecular systems and their dynamics, based on fine-scale data and rational model selection methods through suitable path-space (dynamics-based) information criteria. The proposed methods are tested against a wide range of high-dimensional stochastic processes, ranging from complex biochemical reaction networks with hundreds of parameters, to spatially extended Kinetic Monte Carlo models in catalysis and Langevin dynamics of interacting molecules with internal degrees of freedom.<br />
<br />
=== Frederic Coquel (Ecole Polytechnique Paris) ===<br />
<br />
''Jin and Xin's Relaxation Solvers with Defect Measure Corrections''<br />
<br />
We present a class of finite volume methods for approximating entropy weak solutions of non-linear hyperbolic PDEs. The main motivation is to resolve discontinuities as well as Glimm's scheme, but without the need for solving Riemann problems exactly. The sharp capture of discontinuities is known to be mandatory in situations where discontinuities are sensitive to viscous perturbations while exact Riemann solutions may not be available (typically in phase transition problems). More generally, sharp capture also prevent discrete shock proles from exhibiting over and undershoots, which is decisive in a many applications (in combustion for instance). We propose to replace exact Riemann solutions by self-similar solutions conveniently derived from the Jin-Xin's relaxation framework. In the limit of a vanishing relaxation time, the relaxation source term exhibits Dirac measures concentrated on the discontinuities. We show how to handle those so-called defect measures in order to exactly capture propagating shock solutions while achieving computational efficiencies. The lecture will essential focus on the convergence analysis in the scalar setting. A special attention is paid to the consistency of the proposed correction with respect to the entropy condition. We prove the convergence of the method to the unique Kruvkov's solution.<br />
<br />
=== Lisa Fauci (Tulane) ===<br />
<br />
''Flagellar motility: negotiating sticky elastic bonds and viscoelastic networks''<br />
<br />
We will discuss a Stokes fluid model that incorporates forces due to elastic structures in the fluid environment of the actuated flagellum. We will present recent computational investigations of hyperactivated sperm detachment from oviductal epithelium as well as swimming through viscoelastic networks. <br />
<br />
=== Paulo Arratia (U Penn) ===<br />
<br />
''Pulling and pushing in complex fluids''<br />
<br />
Many microorganisms evolve in media that contain (bio)-polymers and/or solids; examples include cervical mucus, intestinal fluid, wet soil, and tissues. These so-called complex fluids often exhibit non-Newtonian rheological behavior such as shear-thinning viscosity and elasticity. In this talk, I will discuss recent experiments on the effects of fluid elasticity on the swimming behavior of microorganisms. Two main microorganisms are used, the green algae C. reinhardtii (a puller-type swimmer) and the bacterium E. coli (a pusher-type swimmer). For the case of pullers (C. reinhardtii), we find that fluid elasticity hinders the cell’s overall swimming speed but leads to an increase in the cell’s flagellum beating frequency. The beating kinematics and flagellum waveforms are also significantly modified by fluid elasticity. For the case of pushers (E. coli), the presence of even small amount of polymers in the medium suppresses the bacteria run-and-tumble mechanism. The bacteria spend more time in ballistic mode and swim faster as well. Single molecule experiments using fluorescently labeled DNA show that the flow fields generated by E. coli are able to stretch initially coiled polymer molecules and thus induce elastic stresses in fluid. These results demonstrate the intimate link between swimming kinematics and fluid rheology and that one can control the spreading and motility of microorganisms by tuning fluid properties.<br />
<br />
=== Tao Zhou (Chinese Academy of Sciences) ===<br />
<br />
''The Christoffel function weighted least-squares for stochastic collocation approximations: applications to Uncertainty Quantification''<br />
<br />
We shall consider the multivariate stochastic collocation methods on unstructured grids. The motivation for such a study is the applications in parametric Uncertainty Quantification (UQ). We will first give a general framework of stochastic collocation methods, which include approaches such as compressed sensing, least-squares, and interpolation. Particular attention will be then given to the least-squares approach, and we will review recent progresses in this topic.<br />
<br />
=== Bin Cheng (University of Surrey) ===<br />
<br />
'Error estimates and 2nd order corrections to reduced fluid models''<br />
<br />
In this PDE analysis work, I will discuss the application of time-averaging in getting rigorous error estimates of some reduced fluid models, including the incompressible approximation and quasi-geostrophic approximation. The spatial boundary can be present as a non-penetrable solid wall. I will show a somewhat surprising result on the epsilon^2 accuracy of incompressible approximation of Euler equations, thanks to several decoupling properties.<br />
<br />
=== Stephen Wright (UW) ===<br />
<br />
''The revival of coordinate descent methods''<br />
<br />
The approach of minimizing a function by successively fixing most of its variables and minimizing with respect to the others dates back many years, and has been applied in an enormous range of applications. Until recently, however, the approach did not command much respect among optimization researchers; only a few prominent individuals took it seriously. Recent years have seen an explosion in applications, particularly in data analysis, which has driven a new wave of research into variants of coordinate descent and their convergence properties. Such aspects as randomization in the choice of variants to fix and relax, acceleration methods, extension to regularized objectives, and parallel implementation have commanded a good deal of attention during the past five years. In this lecture, I will survey these recent developments, then focus on recent work on asynchronous parallel implementations for multicore computers. An analysis of the properties of the latter algorithms shows that near-linear speedup can be expected, up to a number of processors that depends on the coupling between the variables.<br />
<br />
This talk covers joint work with Ji Liu and other colleagues.<br />
<br />
=== Elaine Spiller (Marquette) ===<br />
<br />
TBA<br />
<br />
=== Murad Banaji (University of Portsmouth) ===<br />
<br />
''Nonexpansivity in chemical reaction networks''<br />
<br />
This work is motivated by the observation that quite often systems of differential equations describing chemical reaction networks (CRNs) display simple global behaviour such as convergence of all orbits to a unique equilibrium under only weak and physically reasonable assumptions on the reaction rates (kinetics). We are led to wonder if the structure of a CRN may sometimes force some distance between solutions to decrease (or at least not increase) with time. If so, how can we find this nonincreasing quantity? We explore different ways in which CRNs can define nonexpansive semiflows (recall that a semiflow <math>(\phi_t)_{t \geq 0}</math> on some Banach space <math>(X, |\cdot|)</math> is nonexpansive if <math>|\phi_t(x)-\phi_t(y)| \leq |x-y|</math> for all <math>x,y \in X</math> and all <math>t \geq 0</math>). It turns out that in CRNs the natural evolution of chemical concentrations may be nonexpansive; or a nonexpansive semiflow may be obtained from the evolution of the so-called "extents" of reactions. In both cases we may be able to draw global conclusions about convergence of chemical concentrations. In each case the challenge is to find the correct norm to get nonexpansivity for arbitrary kinetics. To construct such norms and show nonexpansivity we appeal to the theory of monotone dynamical systems. Families of CRNs which can be analysed in this way are presented; however characterising fully the class of CRNs to which this theory applies remains an open - and undoubtedly difficult - task.<br />
<br />
This is joint work with Bas Lemmens (University of Kent) and Pete Donnell (University of Portsmouth).</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=9477Applied/ACMS2015-03-05T18:01:48Z<p>Craciun: /* Spring 2015 Semester */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://lists.math.wisc.edu/listinfo/acms mailing list] website.<br />
<br />
<br><br />
<br />
== Spring 2015 Semester ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Jan 23<br />
|[http://www.maths.dundee.ac.uk/ikyza/IreneKyza/ Irene Kyza] (U Dundee)<br />
|''[[Applied/ACMS/absS15#Irene Kyza (U Dundee)|Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control]]''<br />
|Shi Jin <br />
|-<br />
|Jan 30<br />
|[http://www.aos.wisc.edu/~dvimont/ Daniel Vimont] (UW)<br />
|''[[Applied/ACMS/absS15#Daniel Vimont (UW)|Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events]]''<br />
|Sam, Saverio<br />
|<br />
|-<br />
|Feb 13<br />
|[http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] (UW)<br />
|''[[Applied/ACMS/absS15#Saverio Spagnolie (UW)|Sedimentation in viscous fluids: flexible filaments and boundary effects]]''<br />
|<br />
|-<br />
|Feb 20<br />
|[http://jbfreund.mechse.illinois.edu/ Jonathan Freund] (U Illinois)<br />
|''[[Applied/ACMS/absS15#Jonathan Freund (UIUC)|Adjoint-based optimization for understanding and reducing flow noise]]''<br />
|Saverio<br />
|-<br />
|Feb 27<br />
|[http://people.math.umass.edu/~markos/ Markos Katsoulakis] (U Mass Amherst)<br />
|''[[Applied/ACMS/absS15#Markos Katsoulakis (U Mass Amherst)|Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics]]''<br />
|Shi Jin<br />
|-<br />
|Mar 6<br />
|[https://www.ljll.math.upmc.fr/~coquel/node2.html Frederic Coquel] (Ecole Polytechnique Paris)<br />
|''[[Applied/ACMS/absS15#Frederic Coquel (Ecole Polytechnique Paris)|Jin and Xin's Relaxation Framework with Defect Measure Corrections]]''<br />
|Shi Jin<br />
|-<br />
|Mar 13<br />
|[http://dauns.math.tulane.edu/~ljf/ Lisa Fauci] (Tulane)<br />
|''[[Applied/ACMS/absS15#Lisa Fauci (Tulane)|TBA]]''<br />
|Saverio<br />
|-<br />
|Mar 20<br />
|[http://www.seas.upenn.edu/directory/profile.php?ID=3 Paulo Arratia] (U Penn)<br />
|''[[Applied/ACMS/absS15#Paulo Arratia (U Penn)|TBA]]''<br />
|Saverio<br />
|-<br />
|''Wed. Mar 25'', '''VV 321'''<br />
|[http://www.cc.ac.cn/staff/tzhou.html Tao Zhou] (Chinese Academy of Sciences)<br />
|''[[Applied/ACMS/absS15#Tao Zhou (Chinese Academy of Sciences)|The Christoffel function weighted least-squares for stochastic<br />
collocation approximations: applications to Uncertainty Quantification]]''<br />
|Shi Jin<br />
|-<br />
|Apr 3<br />
|<br />
|Spring break<br />
|<br />
|-<br />
|''Wed. Apr 8'', '''VV 321'''<br />
|[http://personal.maths.surrey.ac.uk/st/bc0012/ Bin Cheng] (University of Surrey)<br />
|''[[Applied/ACMS/absS15#Bin Cheng (University of Surrey)|TBA]]''<br />
|Shi Jin<br />
|<br />
|-<br />
|Apr 10<br />
|[http://banajim.myweb.port.ac.uk/ Murad Banaji] (University of Portsmouth)<br />
|''[[Applied/ACMS/absS15#Murad Banaji (University of Portsmouth)| Nonexpansivity in chemical reaction networks]]''<br />
|Craciun<br />
|<br />
|-<br />
|Apr 17<br />
|[http://pages.cs.wisc.edu/~swright/ Stephen Wright] (UW)<br />
|''[[Applied/ACMS/absS15#Stephen Wright (UW)|TBA]]''<br />
|Saverio<br />
|-<br />
|Apr 24<br />
|[https://vivo.brown.edu/display/tpowers Thomas Powers] (Brown)<br />
|''[[Applied/ACMS/absS15#Thomas Powers (Brown)|TBA]]''<br />
|Saverio<br />
|-<br />
|May 1<br />
|[http://www.marquette.edu/mscs/facstaff-spiller.shtml Elaine Spiller] (Marquette)<br />
|''[[Applied/ACMS/absS15#Elaine Spiller (Marquette)|TBA]]''<br />
|Budisic<br />
|}<br />
<br />
<br><br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS15&diff=9476Applied/ACMS/absS152015-03-05T17:59:40Z<p>Craciun: /* ACMS Abstracts: Spring 2015 */</p>
<hr />
<div>= ACMS Abstracts: Spring 2015 =<br />
<br />
=== Irene Kyza (U Dundee) ===<br />
<br />
''Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control''<br />
<br />
We discuss recent results on the a posteriori error control and adaptivity for an evolution semilinear convection-diffusion model problem with possible blowup in finite time. This belongs to the broad class of partial differential equations describing e.g., tumor growth,chemotaxis and cell modelling. In particular, we derive a posteriori error estimates that are conditional (estimates which are valid under conditions of a posteriori type) for an interior penalty discontinuous Galerkin (dG) implicit-explicit (IMEX) method using a continuation argument. Compared to a previous work, the obtained conditions are more localised and allow the efficient error control near the blowup time. Utilising the conditional a posteriori estimator we are able to propose an adaptive algorithm that appears to perform satisfactorily. In particular, it leads to good approximation of the blowup time and of the exact solution close to the blowup. Numerical experiments illustrate and complement our theoretical results. This is joint work with A. Cangiani, E.H. Georgoulis, and S. Metcalfe from the University of Leicester.<br />
<br />
=== Daniel Vimont (UW) ===<br />
<br />
''Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events''<br />
<br />
Research on the structure and evolution of individual El Niño / Southern Oscillation (ENSO) events has identified two categories of ENSO event characteristics that can be defined by maximum equatorial SST anomalies centered in the Central Pacific (around the dateline to 150 deg. W; CP events) or in the Eastern Pacific (east of about 150 deg. W; EP events). The distinction between these two events is not just academic: both types of event evolve differently, implying different predictability; the events tend to have different maximum amplitude; and the global teleconnection differs between each type of event. <br />
<br />
In this presentation I will (i) describe the Linear Inverse Modeling (LIM) technique, (ii) apply LIM to determine an empirical dynamical operator that governs the evolution of tropical Pacific climate variability, (iii) define norms under which initial conditions can be derived that optimally lead to growth of CP or EP ENSO events, and (iv) identify patterns of stochastic forcing that are responsible for exciting each type of event.<br />
<br />
=== Saverio Spagnolie (UW) ===<br />
<br />
''Sedimentation in viscous fluids: flexible filaments and boundary effects''<br />
<br />
The deformation and transport of elastic filaments in viscous fluids play central roles in many biological and technological processes. Compared with the well-studied case of sedimenting rigid rods, the introduction of filament compliance may cause a significant alteration in the long-time sedimentation orientation and filament geometry. In the weakly flexible regime, a multiple-scale asymptotic expansion is used to obtain expressions for filament translations, rotations and shapes which match excellently with full numerical simulations. In the highly flexible regime we show that a filament sedimenting along its long axis is susceptible to a buckling instability. Embedding the analytical results for a single filament into a mean-field theory, we show how flexibility affects a well established concentration instability in a sedimenting suspension. <br />
<br />
Another problem of classical interest in fluid mechanics involves the sedimentation of a rigid particle near a wall, but most studies have been numerical or experimental in nature. We have derived ordinary differential equations describing the sedimentation of arbitrarily oriented prolate and oblate spheroids near a vertical or inclined plane wall which may be solved analytically for many important special cases. Full trajectories are predicted which compare favorably with complete numerical simulations performed using a novel double layer boundary integral formulation, a Method of Stresslet Images. Several trajectory-types emerge, termed tumbling, glancing, reversing, and sliding, along with their fully three-dimensional analogues.<br />
<br />
=== Jonathan Freund (UIUC) ===<br />
<br />
''Adjoint-based optimization for understanding and reducing flow noise''<br />
<br />
Advanced simulation tools, particularly large-eddy simulation techniques, are becoming capable of making quality predictions of jet noise for realistic nozzle geometries and at engineering relevant flow conditions. Increasing computer resources will be a key factor in improving these predictions still further. Quality prediction, however, is only a necessary condition for the use of such simulations in design optimization. Predictions do not of themselves lead to quieter designs. They must be interpreted or harnessed in some way that leads to design improvements. As yet, such simulations have not yielded any simplifying principals that offer general design guidance. The turbulence mechanisms leading to jet noise remain poorly described in their complexity. In this light, we have implemented and demonstrated an aeroacoustic adjoint-based optimization technique that automatically calculates gradients that point the direction in which to adjust controls in order to improve designs. This is done with only a single flow solutions and a solution of an adjoint system, which is solved at computational cost comparable to that for the flow. Optimization requires iterations, but having the gradient information provided via the adjoint accelerates convergence in a manner that is insensitive to the number of parameters to be optimized. The talk will review the formulation of the adjoint of the compressible flow equations for optimizing noise-reducing controls and present examples of its use. We will particularly focus on some mechanisms of flow noise that have been revealed via this approach.<br />
<br />
=== Markos Katsoulakis (U Mass Amherst) ===<br />
<br />
''Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics''<br />
<br />
In this talk we discuss path-space information theory-based sensitivity analysis and parameter identification methods for complex high-dimensional dynamics, as well as information-theoretic tools for parameterized coarse-graining of non-equilibrium extended systems. Furthermore, we establish their connections with goal-oriented methods in terms of new, sharp, uncertainty quantification inequalities. The combination of proposed methodologies is capable to (a) handle molecular-level models with a very large number of parameters, (b) address and mitigate the high-variance in statistical estimators, e.g. for sensitivity analysis, in spatially distributed <br />
<br />
Kinetic Monte Carlo (KMC), (c) tackle non-equilibrium processes, typically associated with coupled physicochemical mechanisms, boundary conditions, etc. (such as reaction-diffusion systems), and where even steady states are unknown altogether, e.g. do not have a Gibbs structure. Finally, the path-wise information theory tools, (d) yield a surprisingly simple, tractable and easy-to-implement approach to quantify and rank parameter sensitivities, as well as (e) provide reliable molecular model parameterizations for coarse-grained molecular systems and their dynamics, based on fine-scale data and rational model selection methods through suitable path-space (dynamics-based) information criteria. The proposed methods are tested against a wide range of high-dimensional stochastic processes, ranging from complex biochemical reaction networks with hundreds of parameters, to spatially extended Kinetic Monte Carlo models in catalysis and Langevin dynamics of interacting molecules with internal degrees of freedom.<br />
<br />
=== Tao Zhou (Chinese Academy of Sciences) ===<br />
<br />
''The Christoffel function weighted least-squares for stochastic collocation approximations: applications to Uncertainty Quantification''<br />
<br />
We shall consider the multivariate stochastic collocation methods on unstructured grids. The motivation for such a study is the applications in parametric Uncertainty Quantification (UQ). We will first give a general framework of stochastic collocation methods, which include approaches such as compressed sensing, least-squares, and interpolation. Particular attention will be then given to the least-squares approach, and we will review recent progresses in this topic.<br />
<br />
=== Elaine Spiller (Marquette) ===<br />
<br />
TBA<br />
<br />
=== Murad Banaji (Portsmouth) ===<br />
<br />
''Nonexpansivity in chemical reaction networks''<br />
<br />
This work is motivated by the observation that quite often systems of differential equations describing chemical reaction networks (CRNs) display simple global behaviour such as convergence of all orbits to a unique equilibrium under only weak and physically reasonable assumptions on the reaction rates (kinetics). We are led to wonder if the structure of a CRN may sometimes force some distance between solutions to decrease (or at least not increase) with time. If so, how can we find this nonincreasing quantity? We explore different ways in which CRNs can define nonexpansive semiflows (recall that a semiflow <math>(\phi_t)_{t \geq 0}</math> on some Banach space <math>(X, |\cdot|)</math> is nonexpansive if <math>|\phi_t(x)-\phi_t(y)| \leq |x-y|</math> for all <math>x,y \in X</math> and all <math>t \geq 0</math>). It turns out that in CRNs the natural evolution of chemical concentrations may be nonexpansive; or a nonexpansive semiflow may be obtained from the evolution of the so-called "extents" of reactions. In both cases we may be able to draw global conclusions about convergence of chemical concentrations. In each case the challenge is to find the correct norm to get nonexpansivity for arbitrary kinetics. To construct such norms and show nonexpansivity we appeal to the theory of monotone dynamical systems. Families of CRNs which can be analysed in this way are presented; however characterising fully the class of CRNs to which this theory applies remains an open - and undoubtedly difficult - task.<br />
<br />
This is joint work with Bas Lemmens (University of Kent) and Pete Donnell (University of Portsmouth).</div>Craciunhttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS15&diff=9475Applied/ACMS/absS152015-03-05T17:58:14Z<p>Craciun: /* Murad Banaji (Portsmouth) */</p>
<hr />
<div>= ACMS Abstracts: Spring 2015 =<br />
<br />
=== Irene Kyza (U Dundee) ===<br />
<br />
''Adaptivity and blowup detection for semilinear evolution convection-diffusion equations based on a posteriori error control''<br />
<br />
We discuss recent results on the a posteriori error control and adaptivity for an evolution semilinear convection-diffusion model problem with possible blowup in finite time. This belongs to the broad class of partial differential equations describing e.g., tumor growth,chemotaxis and cell modelling. In particular, we derive a posteriori error estimates that are conditional (estimates which are valid under conditions of a posteriori type) for an interior penalty discontinuous Galerkin (dG) implicit-explicit (IMEX) method using a continuation argument. Compared to a previous work, the obtained conditions are more localised and allow the efficient error control near the blowup time. Utilising the conditional a posteriori estimator we are able to propose an adaptive algorithm that appears to perform satisfactorily. In particular, it leads to good approximation of the blowup time and of the exact solution close to the blowup. Numerical experiments illustrate and complement our theoretical results. This is joint work with A. Cangiani, E.H. Georgoulis, and S. Metcalfe from the University of Leicester.<br />
<br />
=== Daniel Vimont (UW) ===<br />
<br />
''Linear Inverse Modeling of Central and East Pacific El Niño / Southern Oscillation (ENSO) Events''<br />
<br />
Research on the structure and evolution of individual El Niño / Southern Oscillation (ENSO) events has identified two categories of ENSO event characteristics that can be defined by maximum equatorial SST anomalies centered in the Central Pacific (around the dateline to 150 deg. W; CP events) or in the Eastern Pacific (east of about 150 deg. W; EP events). The distinction between these two events is not just academic: both types of event evolve differently, implying different predictability; the events tend to have different maximum amplitude; and the global teleconnection differs between each type of event. <br />
<br />
In this presentation I will (i) describe the Linear Inverse Modeling (LIM) technique, (ii) apply LIM to determine an empirical dynamical operator that governs the evolution of tropical Pacific climate variability, (iii) define norms under which initial conditions can be derived that optimally lead to growth of CP or EP ENSO events, and (iv) identify patterns of stochastic forcing that are responsible for exciting each type of event.<br />
<br />
=== Saverio Spagnolie (UW) ===<br />
<br />
''Sedimentation in viscous fluids: flexible filaments and boundary effects''<br />
<br />
The deformation and transport of elastic filaments in viscous fluids play central roles in many biological and technological processes. Compared with the well-studied case of sedimenting rigid rods, the introduction of filament compliance may cause a significant alteration in the long-time sedimentation orientation and filament geometry. In the weakly flexible regime, a multiple-scale asymptotic expansion is used to obtain expressions for filament translations, rotations and shapes which match excellently with full numerical simulations. In the highly flexible regime we show that a filament sedimenting along its long axis is susceptible to a buckling instability. Embedding the analytical results for a single filament into a mean-field theory, we show how flexibility affects a well established concentration instability in a sedimenting suspension. <br />
<br />
Another problem of classical interest in fluid mechanics involves the sedimentation of a rigid particle near a wall, but most studies have been numerical or experimental in nature. We have derived ordinary differential equations describing the sedimentation of arbitrarily oriented prolate and oblate spheroids near a vertical or inclined plane wall which may be solved analytically for many important special cases. Full trajectories are predicted which compare favorably with complete numerical simulations performed using a novel double layer boundary integral formulation, a Method of Stresslet Images. Several trajectory-types emerge, termed tumbling, glancing, reversing, and sliding, along with their fully three-dimensional analogues.<br />
<br />
=== Jonathan Freund (UIUC) ===<br />
<br />
''Adjoint-based optimization for understanding and reducing flow noise''<br />
<br />
Advanced simulation tools, particularly large-eddy simulation techniques, are becoming capable of making quality predictions of jet noise for realistic nozzle geometries and at engineering relevant flow conditions. Increasing computer resources will be a key factor in improving these predictions still further. Quality prediction, however, is only a necessary condition for the use of such simulations in design optimization. Predictions do not of themselves lead to quieter designs. They must be interpreted or harnessed in some way that leads to design improvements. As yet, such simulations have not yielded any simplifying principals that offer general design guidance. The turbulence mechanisms leading to jet noise remain poorly described in their complexity. In this light, we have implemented and demonstrated an aeroacoustic adjoint-based optimization technique that automatically calculates gradients that point the direction in which to adjust controls in order to improve designs. This is done with only a single flow solutions and a solution of an adjoint system, which is solved at computational cost comparable to that for the flow. Optimization requires iterations, but having the gradient information provided via the adjoint accelerates convergence in a manner that is insensitive to the number of parameters to be optimized. The talk will review the formulation of the adjoint of the compressible flow equations for optimizing noise-reducing controls and present examples of its use. We will particularly focus on some mechanisms of flow noise that have been revealed via this approach.<br />
<br />
=== Markos Katsoulakis (U Mass Amherst) ===<br />
<br />
''Information Theory methods for parameter sensitivity and coarse-graining of high-dimensional stochastic dynamics''<br />
<br />
In this talk we discuss path-space information theory-based sensitivity analysis and parameter identification methods for complex high-dimensional dynamics, as well as information-theoretic tools for parameterized coarse-graining of non-equilibrium extended systems. Furthermore, we establish their connections with goal-oriented methods in terms of new, sharp, uncertainty quantification inequalities. The combination of proposed methodologies is capable to (a) handle molecular-level models with a very large number of parameters, (b) address and mitigate the high-variance in statistical estimators, e.g. for sensitivity analysis, in spatially distributed <br />
<br />
Kinetic Monte Carlo (KMC), (c) tackle non-equilibrium processes, typically associated with coupled physicochemical mechanisms, boundary conditions, etc. (such as reaction-diffusion systems), and where even steady states are unknown altogether, e.g. do not have a Gibbs structure. Finally, the path-wise information theory tools, (d) yield a surprisingly simple, tractable and easy-to-implement approach to quantify and rank parameter sensitivities, as well as (e) provide reliable molecular model parameterizations for coarse-grained molecular systems and their dynamics, based on fine-scale data and rational model selection methods through suitable path-space (dynamics-based) information criteria. The proposed methods are tested against a wide range of high-dimensional stochastic processes, ranging from complex biochemical reaction networks with hundreds of parameters, to spatially extended Kinetic Monte Carlo models in catalysis and Langevin dynamics of interacting molecules with internal degrees of freedom.<br />
<br />
=== Tao Zhou (Chinese Academy of Sciences) ===<br />
<br />
''The Christoffel function weighted least-squares for stochastic collocation approximations: applications to Uncertainty Quantification''<br />
<br />
We shall consider the multivariate stochastic collocation methods on unstructured grids. The motivation for such a study is the applications in parametric Uncertainty Quantification (UQ). We will first give a general framework of stochastic collocation methods, which include approaches such as compressed sensing, least-squares, and interpolation. Particular attention will be then given to the least-squares approach, and we will review recent progresses in this topic.<br />
<br />
=== Elaine Spiller (Marquette) ===<br />
<br />
TBA<br />
<br />
=== Murad Banaji (Portsmouth) ===<br />
<br />
"Nonexpansivity in chemical reaction networks"<br />
<br />
This work is motivated by the observation that quite often systems of differential equations describing chemical reaction networks (CRNs) display simple global behaviour such as convergence of all orbits to a unique equilibrium under only weak and physically reasonable assumptions on the reaction rates (kinetics). We are led to wonder if the structure of a CRN may sometimes force some distance between solutions to decrease (or at least not increase) with time. If so, how can we find this nonincreasing quantity? We explore different ways in which CRNs can define nonexpansive semiflows (recall that a semiflow <math>(\phi_t)_{t \geq 0}</math> on some Banach space <math>(X, |\cdot|)</math> is nonexpansive if <math>|\phi_t(x)-\phi_t(y)| \leq |x-y|</math> for all <math>x,y \in X</math> and all <math>t \geq 0</math>). It turns out that in CRNs the natural evolution of chemical concentrations may be nonexpansive; or a nonexpansive semiflow may be obtained from the evolution of the so-called "extents" of reactions. In both cases we may be able to draw global conclusions about convergence of chemical concentrations. In each case the challenge is to find the correct norm to get nonexpansivity for arbitrary kinetics. To construct such norms and show nonexpansivity we appeal to the theory of monotone dynamical systems. Families of CRNs which can be analysed in this way are presented; however characterising fully the class of CRNs to which this theory applies remains an open - and undoubtedly difficult - task.<br />
<br />
This is joint work with Bas Lemmens (University of Kent) and Pete Donnell (University of Portsmouth).</div>Craciun