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All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.


== Fall 2015  ==
<!-- ==[[Tentative Colloquia|Tentative schedule for next semester]] == -->
 
Go to next semester, [[Colloquia/Spring 2016|Spring 2016]].


==Fall 2017==


{| cellpadding="8"
{| cellpadding="8"
!align="left" | date
!align="left" | Date 
!align="left" | speaker
!align="left" | Speaker
!align="left" | title
!align="left" | Title
!align="left" | host(s)
!align="left" | Host(s)
|-
| '''September 4'''
| [http://homepages.math.uic.edu/~isaac/  Isaac Goldbring] (UIC)   
| [[Colloquia#September 4:  Isaac Goldbring (UIC) | On Kirchberg's embedding problem]]
| Andrews/Lempp
|-
|-
| '''September 11'''
|September 8
| [https://sites.google.com/site/doronpuder/ Doron Puder] (IAS)
| [https://sites.google.com/a/wisc.edu/theresa-c-anderson/home/ Tess Anderson] (Madison)
| [[Colloquia#September 11: Doron Puder (IAS) | Word-Measures on Groups]]
|[[#September 8: Tess Anderson (Madison) | A Spherical Maximal Function along the Primes  ]]
| Gurevich
| Yang
|
|-
|-
| '''September 18'''
|September 15
| [http://homepages.math.uic.edu/~coskun/ Izzet Coskun] (UIC)
|
| [[Colloquia#September 18:  Izzet Coskun (UIC) | The geometry of points in the plane]]  
|[[#|   ]]
| Erman
|
|
|
|-
|-
| '''September 25'''  
|September 22, '''9th floor'''
| [https://pantherfile.uwm.edu/ourmazd/www/ Abbas Ourmazd] (UW-Milwaukee)  
| Jaeyoung Byeon (KAIST)
|   [[Colloquia#September 25: Abbas Ourmazd (UW-Milwaukee) | Structure and Dynamics from Random Observations]]
|[[#September 22: Jaeyoung Byeon (KAIST) | Patterns formation for elliptic systems with large interaction forces  ]]
| Mitchell
| Rabinowitz & Kim
|
|-
|-
| '''October 2'''  
|September 29
|  
|
|  
|[[# TBA|  TBA  ]]
|
|
|-
|October 6,  '''9th floor'''
| [http://www3.nd.edu/~jhauenst/ Jonathan Hauenstein] (Notre Dame)
|[[#October 6: Jonathan Hauenstein (Notre Dame) |  Real solutions of polynomial equations ]]
| Boston
|  
|  
|-
|-
| '''October 9'''  
|October 13, '''9th floor'''
| Chanwoo Kim 
| [http://www.tomokokitagawa.com/ Tomoko L. Kitagawa] (Berkeley)
| [[Colloquia#October 9: Chanwoo Kim  | Coercivity of the Boltzmann equation ]]
|[[#October 13: Tomoko Kitagawa (Berkeley) | A Global History of Mathematics from 1650 to 2017 ]]
|
| Max
|
|-
|-
| '''October 16'''
|October 20
| [http://mysite.science.uottawa.ca/hsalmasi/ Hadi Salmasian] (Ottawa)  
| [http://cims.nyu.edu/~pgermain/ Pierre Germain] (Courant, NYU)  
| [[Colloquia#October 16: Hadi Salmasian (University of Ottawa) | The Capelli problem and spectrum of invariant differential operators]]
|[[#October 13: Pierre Germain (Courant, NYU) | Stability of the Couette flow in the Euler and Navier-Stokes equations ]]
| Gurevich
| Minh-Binh Tran
|
|-
|-
| '''October 23'''
|October 27
| Lu Wang (UW)   <!-- [webpage Speaker Name] (University) -->   
|Stefanie Petermichl (Toulouse)
|   [[Colloquia#October23:  Lu Wang (UW) | Singularities of Mean Curvature Flow]]
|[[# TBA| TBA ]]
| <!-- host -->
| Stovall, Seeger
|
|-
|-
| '''October 30'''
|We, November 1
|   [http://people.brandeis.edu/~charney/Charney15.html Ruth Charney] (Brandeis)    
|Shaoming Guo (Indiana)
| [[Colloquia#October 30: Ruth Charney (Brandeis) | Finding hyperbolic behavior in non-hyperbolic spaces]]
|[[# TBA|  TBA ]]
| Dymarz
|
|
|-
|-
| '''November 6'''
|November 3
| [http://people.seas.harvard.edu/~chr/ Chris Rycroft] (Harvard)   
|[[# TBA|  TBA ]]
| [[Colloquia#November 6: Chris Rycroft (Harvard) | Interfacial dynamics of dissolving objects in fluid flow]]
|
| Spagnolie
|
|-
|-
| '''November 13'''
|November 10
|   [http://pages.iu.edu/~fisherdm/ David Fisher] (Indiana)     
| Reserved for possible job talks
| [[Colloquia#November 13: David Fisher (Indiana) | Rigidity of quasi-isometric embeddings]]
|[[# TBA|  TBA ]]
| Dymarz
|
|
|-
|-
| '''November 20'''
|November 17
| Avy Soffer (Rutgers)
| Reserved for possible job talks
|   [[Colloquia#November 20: Avy Soffer (Rutgers) | Nonlinear Long Range Scattering and Normal Form Analysis]]
|[[# TBA|  TBA ]]
| Minh Binh Tran
|
|
|-
|-
| '''November 27'''  
|November 24
University Holiday
|'''Thanksgiving break'''
| No Colloquium
|[[# TBATBA  ]]
|
|
|
|-
|-
| '''December 4'''
|December 1
Charlie Smart (Uchicago)
| Reserved for possible job talks
|[[# TBA|  TBA ]]
|
|
|
| Street
|-
|-
| '''December 11'''
|December 8
| [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault] (UW Madison)
| Reserved for possible job talks
|[[# TBA|  TBA  ]]
|
|
|
|
|-
|}
|}


== Abstracts ==
== Fall Abstracts ==
=== September 8: Tess Anderson (Madison) ===
Title: A Spherical Maximal Function along the Primes


===September 4: Isaac Goldbring (UIC) ===
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.
Title: On Kirchberg's embedding problem


Abstract: In his seminal work on the classification program for nuclear C*-algebras, Kirchberg showed that a particular C*-algebra, the Cuntz algebra O2, plays a seminal role. Subsequent work with Chris Phillips showed that O2 also plays a prominent role in regards to the wider class of exact C*-algebras, and this led Kirchberg to conjecture that every C*-algebra is finitely representable in O2, that is, is embeddable in an ultrapower of O2. The main goal of this talk is to sketch a proof of a local finitary reformulation of this conjecture of Kirchberg. The proof uses model theory and in particular the notion of model-theoretic forcing. No knowledge of C*-algebras or model theory will be assumed. This is joint work with Thomas Sinclair.


====  ====
=== September 22: Jaeyoung Byeon (KAIST) ===
Title: Patterns formation for elliptic systems with large interaction forces


===September 11: Doron Puder (IAS) ===
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.
Title: Word-Measures on Groups.


Abstract: Let w be a word in the free group on k generators, and let G be a finite (compact) group. The word w induces a measure on G by substituting the letters of w with k independent uniformly (Haar) chosen random elements of G and evaluating the product. Questions about word-measures on groups attracted attention in recent years both for their own sake and as a tool to analyze random walks on groups.
===October 6: Jonathan Hauenstein (Notre Dame) ===
Title: Real solutions of polynomial equations


We will explain some properties of word-measure, give examples and state conjectures. We will also talk about recent results regarding word-measures on symmetric groups and word-measures on unitary groups.
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.
====  ====


===September 18: Izzet Coskun (UIC) ===
===October 13: Tomoko Kitagawa (Berkeley) ===
Title: The geometry of points in the plane
Title: A Global History of Mathematics from 1650 to 2017


Abstract: Grothendieck's Hilbert scheme of points is a smooth  compactification of the configuration space of points in the plane. It has close connections with combinatorics, representation theory, mathematical physics and algebraic geometry. In this talk, I will survey some of the basic properties of this beautiful space. If time permits, I will discuss joint work with Arcara, Bertram and Huizenga on codimension one subvarieties of the Hilbert scheme.
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?
====  ====


===September 25: Ourmazd (UW-Milwaukee) ===
===October 13: Pierre Germain (Courant, NYU) ===
Title: Structure and Dynamics from Random Observations
Title: Stability of the Couette flow in the Euler and Navier-Stokes equations


Abstract: At weddings, the bridal photo is taken under bright lights, with the happy couple holding still. Traditionally in science, the “best” observations are those with the largest signal from the most tightly controlled system. Like bridal photos, the results are not always exciting. In a wide range of phenomena – from the dance of proteins during their function, to the breaking of molecular bonds on the femtosecond scale – tight control is neither possible, nor desirable. Modern data-analytical techniques extract far more information from random sightings than usually obtained from set-piece experiments.
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).
I will describe on-going efforts to extract structural and dynamical information from noisy, random snapshots. Examples will include YouTube videos, the structure and conformations of molecular machines such as the ribosome, and the ultrafast dynamics of bond-breaking in small molecules like nitrogen.


==== October 9: Chanwoo Kim  ====
== Spring 2018 ==
Title: Coercivity in the Boltzmann equation


Abstract: The Boltzmann equation is a fundamental equation of rarefied gas. Around the natural steady state, so called Maxwellian, a linearized operator is degenerated coercive. In this talk we will see how to recover this degenerated part so that the linearized operator is coercive effectively.
{| cellpadding="8"
!align="left" | date 
!align="left" | speaker
!align="left" | title
!align="left" | host(s)
|-
| March 16
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)
|[[# TBA|  TBA  ]]
| WIMAW
|
|-
|April 4 (Wednesday)
| [http://math.ucr.edu/home/baez/ John Baez] (UC Riverside)
|[[# TBA|  TBA  ]]
| Craciun
|
|-
| April 6
| Reserved
|[[# TBA|  TBA  ]]
| Melanie
|
|-
| April 13
| [https://www.math.brown.edu/~jpipher/ Jill Pipher] (Brown)
|[[# TBA|  TBA  ]]
| WIMAW
|
|-
|date
| person (institution)
|[[# TBA|  TBA  ]]
| hosting faculty
|
|-
|date
| person (institution)
|[[# TBA|  TBA  ]]
| hosting faculty
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|-
|date
| person (institution)
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| hosting faculty
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|-
|date
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|[[# TBA|  TBA  ]]
| hosting faculty
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|-
|date
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|[[# TBA|  TBA  ]]
| hosting faculty
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|-
|date
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|-
|date
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|-
|date
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|-
|date
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|-
|date
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|
|}


=== October 16: Hadi Salmasian (Ottawa)===
== Spring Abstracts ==
Title: The Capelli problem and spectrum of invariant differential operators


Abstract: The Capelli identity is a mysterious result in classical invariant theory with a long history. It was demystified by Roger Howe, who used it in an ingenious and elegant fashion in the modern theory of representations of real reductive groups. In this talk, I will introduce the Capelli identity, and exhibit the relationship between an extension of this identity with certain polynomials which describe the spectrum of invariant differential operators on symmetric superspaces. These polynomials are analogs of the Jack and Knop-Sahi/Okounkov-Olshanski polynomials. This talk is based on a joint project with Siddhartha Sahi.
=== <DATE>: <PERSON> (INSTITUTION) ===
Title: <TITLE>


=== October 23: Lu Wang===
Abstract: <ABSTRACT>


Title: Singularities of Mean Curvature Flow


Abstract: Mean curvature flow (MCF) of hypersurfaces is the gradient flow of volume functional, which decreases the volume in its steepest way. Any compact MCF will develop singularities in finite time, which are modeled by self-shrinkers, a special class of solutions of MCF. Recently, Colding-Minicozzi proposed a dynamical approach to study the singularities formation of MCF. In this talk, I will survey some progress in the classification of self-shrinkers (from different point views) as well as some major open problems. Part of the work is joint with Jacob Bernstein.
== Past Colloquia ==
 
===October 30: Ruth Charney (Brandeis)===
 
Title: Finding hyperbolic behavior in non-hyperbolic spaces


Abstract: In the early 90’s, Gromov introduced a notion of hyperbolicity for geodesic metric spaces.  The study of groups of isometries of such spaces has been an underlying theme of much of the work in geometric group theory since that time.  Many geodesic metric spaces, while not hyperbolic in the sense of Gromov, nonetheless display some hyperbolic-like behavior.  I will discuss a new invariant, the Morse boundary of a space, designed to capture this behavior.  This is joint work with Harold Sultan, together with recent work of my students Matt Cordes and Devin Murray.
[[Colloquia/Blank|Blank Colloquia]]


===November 6: Chris Rycroft (Harvard)===
[[Colloquia/Spring2017|Spring 2017]]


Title: Interfacial dynamics of dissolving objects in fluid flow
[[Archived Fall 2016 Colloquia|Fall 2016]]


Abstract: An advection--diffusion-limited dissolution model of an object being eroded by a two-dimensional potential flow will be presented. By taking advantage of conformal invariance of the model, a numerical method will be introduced that tracks the evolution of the object boundary in terms of a time-dependent Laurent series. Simulations of several dissolving objects will be shown, all of which show collapse to a single point in finite time. The simulations reveal a surprising connection between the position of the collapse point and the initial Laurent coefficients, which was subsequently derived analytically using residue calculus.
[[Colloquia/Spring2016|Spring 2016]]


===November 13: David Fisher (Indiana)===
[[Colloquia/Fall2015|Fall 2015]]
 
Title: Rigidity of quasi-isometric embeddings
 
Abstract:  In geometric group theory, one defines a metric
on finitely generated groups and then asks when algebraic
properties are related to metric ones.  The most famous
example is Gromov's theorem on polynomial growth
which state that a group has polynomial growth iff
it has a finite index subgroup which is nilpotent.
In this talk I will focus on when a geometric mapping
is in fact algebraic and so an isomorphism or homomorphism. 
For the case of isomorphisms, this phenomena was first
discovered by Schwartz, with other examples followed in work of
Farb-Schwartz and Eskin.  I will talk about the first results
of this kind for homomorphisms that are not onto;  this
is joint work with Thang Nguyen.  The talk will be accessible
to graduate students.
 
===November 20: Avy Soffer===
 
Nonlinear Long Range Scattering and Normal Form Analysis"
 
Abstract
 
First I will describe the source and nature of long range dynamics in general.
This fundamental effect is responsible to the change in the asymptotic behavior of the system at large times.
It is present in Coulomb and Gravitational dynamics, in theories with mass-less particles (gauge theories) and in low power nonlinear dispersive and hyperbolic equations.
Then, I will describe new results and new Normal Form techniques to deal with the nonlinear Klein-Gordon equation in one dimension, with quadratic and variable coefficient cubic nonlinearity. This problem exhibits a striking resonant interaction between the spatial frequencies of the nonlinear coefficients and the temporal oscillations of the solutions. We prove global existence and (in L-infinity) scattering as well as a certain kind of strong smoothness for the solution at time-like infinity; it is based on several new classes of normal-form transformations. The analysis also shows the limited smoothness of the solution, in the presence of the resonances. In particular we observe the phenomena of growth of some Invariant Sobolev norm of high order. This seems to be generic for such nonlinear systems.
 
== Past Colloquia ==


[[Colloquia/Spring2014|Spring 2015]]
[[Colloquia/Spring2014|Spring 2015]]

Revision as of 20:30, 20 October 2017


Mathematics Colloquium

All colloquia are on Fridays at 4:00 pm in Van Vleck B239, unless otherwise indicated.


Fall 2017

Date Speaker Title Host(s)
September 8 Tess Anderson (Madison) A Spherical Maximal Function along the Primes Yang
September 15
September 22, 9th floor Jaeyoung Byeon (KAIST) Patterns formation for elliptic systems with large interaction forces Rabinowitz & Kim
September 29 TBA
October 6, 9th floor Jonathan Hauenstein (Notre Dame) Real solutions of polynomial equations Boston
October 13, 9th floor Tomoko L. Kitagawa (Berkeley) A Global History of Mathematics from 1650 to 2017 Max
October 20 Pierre Germain (Courant, NYU) Stability of the Couette flow in the Euler and Navier-Stokes equations Minh-Binh Tran
October 27 Stefanie Petermichl (Toulouse) TBA Stovall, Seeger
We, November 1 Shaoming Guo (Indiana) TBA
November 3 TBA
November 10 Reserved for possible job talks TBA
November 17 Reserved for possible job talks TBA
November 24 Thanksgiving break TBA
December 1 Reserved for possible job talks TBA
December 8 Reserved for possible job talks TBA

Fall Abstracts

September 8: Tess Anderson (Madison)

Title: A Spherical Maximal Function along the Primes

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.


September 22: Jaeyoung Byeon (KAIST)

Title: Patterns formation for elliptic systems with large interaction forces

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.

October 6: Jonathan Hauenstein (Notre Dame)

Title: Real solutions of polynomial equations

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.

October 13: Tomoko Kitagawa (Berkeley)

Title: A Global History of Mathematics from 1650 to 2017

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?

October 13: Pierre Germain (Courant, NYU)

Title: Stability of the Couette flow in the Euler and Navier-Stokes equations

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).

Spring 2018

date speaker title host(s)
March 16 Anne Gelb (Dartmouth) TBA WIMAW
April 4 (Wednesday) John Baez (UC Riverside) TBA Craciun
April 6 Reserved TBA Melanie
April 13 Jill Pipher (Brown) TBA WIMAW
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty
date person (institution) TBA hosting faculty

Spring Abstracts

<DATE>: <PERSON> (INSTITUTION)

Title: <TITLE>

Abstract: <ABSTRACT>


Past Colloquia

Blank Colloquia

Spring 2017

Fall 2016

Spring 2016

Fall 2015

Spring 2015

Fall 2014

Spring 2014

Fall 2013

Spring 2013

Fall 2012