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−  __NOTOC__
 
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 = Mathematics Colloquium =   = Mathematics Colloquium = 
   
 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 2013 ==  +  The calendar for spring 2019 can be found [[Colloquia/Spring2019here]]. 
 +  
 +  ==Spring 2019== 
   
 { 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) 
     
−  Sept 6  +  Jan 25 
−  [http://people.math.gatech.edu/~mbaker/ Matt Baker] (Georgia Institute of Technology)  +   [http://www.users.miamioh.edu/randrib/ Beata Randrianantoanina] (Miami University Ohio) WIMAW 
−  RiemannRoch for Graphs and Applications  +  [[#Beata Randrianantoanina (Miami University Ohio)  Some nonlinear problems in the geometry of Banach spaces and their applications ]] 
−  Ellenberg  +   Tullia Dymarz 
 +   
     
−  Sept 13  +  Jan 30 '''Wednesday''' 
−  [http://math.wisc.edu/~andrews/ Uri Andrews] (University of Wisconsin)  +   [https://services.math.duke.edu/~pierce/ Lillian Pierce] (Duke University) 
−  A hop, skip, and a jump through the degrees of relative provability  +  [[#Lillian Pierce (Duke University)  Short character sums ]] 
 +   Boston and Street 
     
     
−  Sept 20  +  Jan 31 '''Thursday''' 
−  [http://www.math.neu.edu/people/profile/valeriotoledanolaredo Valerio Toledano Laredo] (Northeastern)  +   [http://www.math.tamu.edu/~dbaskin/ Dean Baskin] (Texas A&M) 
−  Flat connections and quantum groups  +  [[#Dean Baskin (Texas A&M)  Radiation fields for wave equations ]] 
−  Gurevich  +   Street 
 +   
     
−  '''Wed, Sept 25, 2:30PM in B139'''  +  Feb 1 
−  [http://mypage.iu.edu/~alindens/ Ayelet Lindenstrauss] (Indiana University)  +   [https://services.math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke University) 
−  Taylor Series in Homotopy Theory  +  [[# TBA TBA ]] 
−  Meyer  +   Qin 
 +   
     
−  '''Wed, Sept 25''' (LAA lecture)  +  Feb 5 '''Tuesday''' 
−  [http://www.cs.berkeley.edu/~demmel/ Jim Demmel] (Berkeley)
 +   [http://www.math.tamu.edu/~alexei.poltoratski/ Alexei Poltoratski] (Texas A&M University) 
−  CommunicationAvoiding Algorithms for Linear Algebra and Beyond
 +  [[# TBA TBA ]] 
−  Gurevich
 +   Denisov 
−  
 
−  '''Thurs, Sept 26''' (LAA lecture, Joint with Applied Algebra Seminar)
 
−  [http://www.cs.berkeley.edu/~demmel/ Jim Demmel] (Berkeley)
 
−  Implementing CommunicationAvoiding Algorithms
 
−  Gurevich
 
−  
 
−  Sept 27 (LAA lecture)
 
−  [http://www.cs.berkeley.edu/~demmel/ Jim Demmel] (Berkeley)
 
−  Communication Lower Bounds and Optimal Algorithms for Programs that Reference Arrays
 
−  Gurevich
 
−  
 
−  Oct 4
 
−  [http://www.math.tamu.edu/~sottile/ Frank Sottile] (Texas A&M)  
−  Galois groups of Schubert problems
 
−  Caldararu
 
−  
 
−  Oct 11
 
−  [http://math.uchicago.edu/~wilkinso/ Amie Wilkinson] (Chicago)  
−  [[Colloquia#October 11: Amie Wilkinson (Chicago)  Robust mechanisms for chaos]]
 
−  WIMAW (Cladek)
 
−  
 
−  '''Tues, Oct 15, 4PM''' (Distinguished Lecture)
 
−  [http://math.mit.edu/people/profile.php?pid=1222 Alexei Borodin] (MIT)
 
−  [[Colloquia#October 15 (Tue) and October 16 (Wed): Alexei Borodin (MIT)  Integrable probability I]]
 
−  Valko
 
−  
 
−  '''Wed, Oct 16, 2:30PM''' (Distinguished Lecture)
 
−  [http://math.mit.edu/people/profile.php?pid=1222 Alexei Borodin] (MIT)
 
−  [[Colloquia#October 15 (Tue) and October 16 (Wed): Alexei Borodin (MIT)  Integrable probability II]]
 
−  Valko
 
−  
 
−  <strike>Oct 18</strike>
 
−  No colloquium due to the distinguished lecture
 
−    
     
     
−  Oct 25  +  Feb 8 
−  [http://www.math.umn.edu/~garrett/ Paul Garrett] (Minnesota)  +   [https://sites.math.northwestern.edu/~anaber/ Aaron Naber] (Northwestern) 
−  [[Colloquia#October 25: Paul Garrett (Minnesota)  Boundaryvalue problems, generalized functions, and zeros of zeta functions]]  +  [[#Aaron Naber (Northwestern)  A structure theory for spaces with lower Ricci curvature bounds ]] 
−  Gurevich  +   Street 
−  
 
     
     
−  Nov 1  +  Feb 15 
−  [http://www.cs.columbia.edu/~alewko/ Allison Lewko] (Columbia University)  +   
−  On sets of large doubling, Lambda(4) sets, and errorcorrecting codes
 +  [[# TBA TBA ]] 
−  Stovall
 +   
−  
 
−  Nov 8
 
−  [http://www.math.cornell.edu/~riley/ Tim Riley] (Cornell)  
−  [[Colloquia#November 8: Tim Riley (Cornell)  Hydra groups]]
 
−  Dymarz  
−  
 
−  Nov 15 and later
 
−  Reserved
 
     
−  Street
 
−  
 
−  Nov 22
 
−  [http://www.math.uchicago.edu/~tj/ Tianling Jin] (University of Chicago)
 
−  Solutions of some MongeAmpere equations with degeneracy or singularities.
 
−  Bolotin
 
−  
 
−  '''Mon, Nov 25, 4PM'''
 
−  [https://web.math.princeton.edu/~linlin/ Lin Lin] (Lawrence Berkeley National Lab)
 
−  Fast algorithms for electronic structure analysis
 
−  Jin
 
     
−  '''Tue, Nov 26, 4PM, B139'''  +  Feb 22 
−  [http://www.math.cornell.edu/m/People/Faculty/conley Clinton Conley] (Cornell)  +   [https://people.math.osu.edu/cueto.5/ Angelica Cueto] (Ohio State) 
−  [[Colloquia#November 26 (Tuesday): Clinton Conley (Cornell)  Descriptive settheoretic graph theory]]
 +  [[# TBA TBA ]] 
−  Lempp
 +   Erman and Corey 
−  
 
−  '''Mon, Dec 2, 4PM'''
 
−  [http://www.math.northwestern.edu/~slm/ Simon Marshall] (Northwestern)
 
−  [[Colloquia#December 2 (Monday): Simon Marshall (Northwestern)  Semiclassical estimates for eigenfunctions on locally symmetric spaces]]  
−  Denissov
 
−  
 
−  '''Wed, Dec 4, 4PM'''
 
−  [http://math.berkeley.edu/~svs/ Steven Sam] (Berkeley)
 
−  Free Resolutions and Symmetry
 
−  Boston
 
−  
 
−  '''Fri, Dec 6'''
 
−  [http://math.mit.edu/~hand/ Paul Hand] (MIT)
 
−  [[Colloquia#December 6: Paul Hand (MIT)  Simplifications of the lifting approach for quadratic signal recovery problems]]
 
−  Thiffeault  
−  
 
−  '''Fri, Dec. 6 and Sat Dec. 7'''
 
     
−  [http://www.math.umn.edu/~stant001/askey80 Conference in honor of Dick Askey]
 
−  
 
−  
 
−  '''Mon, Dec. 9, 4pm, VV B239'''
 
−  [http://www.cims.nyu.edu/~jacob/ Jacob Bedrossian] (Courant Institute)
 
−  Inviscid damping and the asymptotic stability of planar shear flows in the 2D Euler equations
 
−  Bolotin
 
−  
 
−  '''Wed, Dec 11, 4PM'''
 
−  [http://math.jhu.edu/~lwang/ Lu Wang] (Johns Hopkins)
 
−  Rigidity of Selfshrinkers of Mean Curvature Flow
 
−  Viaclovsky
 
     
−  '''Fri, Dec. 13, 2:25pm, VV 901'''  +  March 4 
−  [http://chanwookim.wordpress.com/ Chanwoo Kim] (Cambridge)
 +   [http://wwwusers.math.umn.edu/~sverak/ Vladimir Sverak] (Minnesota) Wasow lecture 
−  Regularity of the Boltzmann equation in convex domains
 +  [[# TBA TBA ]] 
−  Bolotin
 +   Kim 
−  
 
−  '''Tues, Dec 17, 4PM'''
 
−  [http://www.statslab.cam.ac.uk/~ps422/ Perla Sousi] (Cambridge)  
−  [[Colloquia#December 17: Perla Sousi (Cambridge)  The effect of drift on the volume of the Wiener sausage]]
 
−  Seppalainen
 
−  
 
−  '''Wed, Dec 18, 4PM'''
 
−  [http://users.math.yale.edu/~dc597/ Dustin Cartwright] (Yale)
 
−  [[Colloquia#December 18: Dustin Cartwright (Yale)  Tropical Complexes]]  
−  Gurevich  
−  }
 
−   
−  == Spring 2014 ==
 
−   
−  { cellpadding="8"
 
−  !align="left"  date
 
−  !align="left"  speaker
 
−  !align="left"  title
 
−  !align="left"  host(s)
 
−  
 
−  '''Mon, Jan 6, 4PM'''
 
−  [http://wwwbcf.usc.edu/~lauda/Aaron_Laudas_Page/Home.html Aaron Lauda] (USC)
 
−  [[Colloquia#January 6: Aaron Lauda (USC)  An introduction to diagrammatic categorification]]
 
−  Caldararu
 
−  
 
−  '''Wed, Jan 8, 4PM'''
 
−  [http://www2.math.umd.edu/~kmelnick/ Karin Melnick] (Maryland)
 
−  [[Colloquia#January 8: Karin Melnick (Maryland)  Normal forms for local flows on parabolic geometries]]
 
−  Kent
 
−  
 
−  Jan 10, 4PM
 
−  [http://users.math.yale.edu/~yd82/ Yen Do] (Yale)
 
−  Convergence of Fourier series and multilinear analysis
 
−  Denissov
 
−  
 
−  '''Mon, Jan 13, 4pm'''
 
−  [http://math.stanford.edu/~wangyi/ Yi Wang] (Stanford)
 
−  Isoperimetric Inequality and Qcurvature
 
−  Viaclovsky
 
−  
 
−  '''Wen, Jan 15, 4pm'''
 
−  [http://www.maths.ox.ac.uk/people/profiles/wei.xiang Wei Xiang] (University of Oxford)
 
−  [[Colloquia#January 15: Wei Xiang (University of Oxford) Conservation Laws and Shock Waves]]
 
−  Bolotin
 
−  
 
−  '''Fri, Jan 17, 2:25PM, VV901'''
 
−  [http://www.math.dartmouth.edu/~gillmana/ Adrianna Gillman] (Dartmouth)
 
−  Fast direct solvers for linear partial differential equations
 
−  Thiffeault
 
−  
 
−  '''Thu, Jan 23, 2:25, VV901'''
 
−  [http://www.stat.berkeley.edu/~mshkolni/ Mykhaylo Shkolnikov] (Berkeley)
 
−  [[Colloquia#Thur, Jan 23: Mykhaylo Shkolnikov (Berkeley)  Intertwinings, wave equations and growth models]]
 
−  Seppalainen
 
−  
 
−  Jan 24
 
−  [http://www.yanivplan.com/ Yaniv Plan] (Michigan)
 
−  [http://www.math.wisc.edu/wiki/index.php/Applied/ACMS/absS14#Yaniv_Plan_.28Michigan.29 Lowdimensionality in mathematical signal processing]
 
−  Thiffeault
 
−  
 
−  Jan 31
 
−  [http://csi.usc.edu/~ubli/ubli.html Urbashi Mitra] (USC)
 
−  Underwater Networks: A Convergence of Communications, Control and Sensing
 
−  Gurevich
 
−  
 
−  Feb 7
 
−  David Treumann (Boston College)
 
−  Functoriality, Smith theory, and the Brauer homomorphism
 
−  Street
 
−  
 
−  Feb 14
 
−  [http://www.tc.columbia.edu/academics/index.htm?facid=apk16 Alexander Karp] (Columbia Teacher's College)
 
−  History of Mathematics Education as a Research Field and as Magistra Vitae
 
−  Kiselev
 
−  
 
−  Feb 21
 
−  [http://www.math.uci.edu/~szhitomi/ Svetlana Jitomirskaya] (UCIrvine)
 
−  Analytic quasiperiodic cocycles
 
−  Kiselev
 
−  
 
−  Feb 28
 
−  [http://math.nyu.edu/faculty/shelley/ Michael Shelley] (Courant)
 
     
−  Spagnolie
 
     
−  March 7  +  March 8 
−  [http://www.math.northwestern.edu/people/facultyProfiles/steve.zelditch.html Steve Zelditch] (Northwestern)  +   [https://orion.math.iastate.edu/jmccullo/index.html Jason McCullough] (Iowa State) 
 +  [[# TBA TBA ]] 
 +   Erman 
     
−  Seeger
 
     
−  March 14  +  March 15 
−    +   Maksym Radziwill (Caltech) 
−    +  [[# TBA TBA ]] 
−  
 +   Marshall 
−  
 
−  <strike>March 21</strike>
 
−  '''Spring Break'''  
−  No Colloquium  
     
     
−  March 28  +  March 29 
−  [http://people.math.gatech.edu/~lacey/ Michael Lacey] (GA Tech)  +   Jennifer Park (OSU) 
−  The Two Weight Inequality for the Hilbert Transform  +  [[# TBA TBA ]] 
−  Street  +   Marshall 
−    
−  April 4
 
−  [http://www.math.brown.edu/~res/ Richard Schwartz] (Brown)
 
     
−  MariBeffa
 
     
−  April 11  +  April 5 
−  [http://www.cs.uchicago.edu/people/risi Risi Kondor] (Chicago)  +   JuLee Kim (MIT) 
 +  [[# TBA TBA ]] 
 +   Gurevich 
     
−  Gurevich
 
     
−  April 18 (Wasow Lecture)  +  April 12 
−  [http://mathnt.mat.jhu.edu/sogge/ Christopher Sogge] (Johns Hopkins)  +   Evitar Procaccia (TAMU) 
 +  [[# TBA TBA ]] 
 +   Gurevich 
     
−  Seeger
 
     
−  April 25  +  April 19 
−  [http://www.charlesdoran.net Charles Doran](University of Alberta)  +   [http://www.math.rice.edu/~jkn3/ Jo Nelson] (Rice University) 
 +  [[# TBA TBA ]] 
 +   JeanLuc 
     
−  Song
 
     
−  '''Monday, April 28''' (Distinguished Lecture)  +  April 26 
−  [http://www.msri.org/people/staff/de/ David Eisenbud](Berkeley)  +   [https://www.brown.edu/academics/appliedmathematics/faculty/kavitaramanan/home Kavita Ramanan] (Brown University) 
−  A mystery concerning algebraic plane curves
 +  [[# TBA TBA ]] 
−  Maxim
 +   WIMAW 
−  
 
−  '''Tuesday, April 29''' (Distinguished Lecture)
 
−  [http://www.msri.org/people/staff/de/ David Eisenbud](Berkeley)
 
−  Matrix factorizations old and new
 
−  Maxim
 
−  
 
−  '''Wednesday, April 30''' (Distinguished Lecture)
 
−  [http://www.msri.org/people/staff/de/ David Eisenbud](Berkeley)  
−  Easy solution of polynomial equations over finite fields  
−  Maxim  
−  
 
−  May 2
 
−  [http://www.stat.uchicago.edu/~lekheng/ LekHeng Lim] (Chicago)
 
     
−  Boston
 
     
−  May 9  +  May 3 
−  [http://www.ma.utexas.edu/users/rward/ Rachel Ward] (UT Austin)  +   Tomasz Przebinda (Oklahoma) 
 +  [[# TBA TBA ]] 
 +   Gurevich 
     
−  WIMAW
 
 }   } 
   
 == Abstracts ==   == Abstracts == 
   
−  ===January 6: Aaron Lauda (USC)===  +  ===Beata Randrianantoanina (Miami University Ohio)=== 
   
−  ''An introduction to diagrammatic categorification''
 +  Title: Some nonlinear problems in the geometry of Banach spaces and their applications. 
   
−  Categorification seeks to reveal a hidden layer in mathematical
 +  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. 
−  structures. Often the resulting structures can be combinatorially
 
−  complex objects making them difficult to study. One method of
 
−  overcoming this difficulty, that has proven very successful, is to
 
−  encode the categorification into a diagrammatic calculus that makes
 
−  computations simple and intuitive.
 
   
−  In this talk I will review some of the original considerations that
 +  ===Lillian Pierce (Duke University)=== 
−  led to the categorification philosophy. We will examine how the
 
−  diagrammatic perspective has helped to produce new categorifications
 
−  having profound applications to algebra, representation theory, and
 
−  lowdimensional topology.
 
   
−  ===January 8: Karin Melnick (Maryland)===
 +  Title: Short character sums 
   
−  ''Normal forms for local flows on parabolic geometries''
 +  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 socalled character sum. For example, both understanding the Riemann zeta function or Dirichlet Lfunctions 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. 
   
−  The exponential map in Riemannian geometry conjugates the differential of an isometry at a point with the action of the isometry near the point. It thus provides a linear normal form for all isometries fixing a point. Conformal transformations are not linearizable in general. I will discuss a suite of normal forms theorems in conformal geometry and, more generally, for parabolic geometries, a rich family of geometric structures of which conformal, projective, and CR structures are examples.
 +  ===Dean Baskin (Texas A&M)=== 
   
−  ===January 10, 4PM: Yen Do (Yale)===
 +  Title: Radiation fields for wave equations 
   
−  ''Convergence of Fourier series and multilinear analysis''
 +  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. 
   
−  Almost everywhere convergence of the Fourier series of square
 +  ===Aaron Naber (Northwestern)=== 
−  integrable functions was first proved by Lennart Carleson in 1966, and
 
−  the proof has lead to deep developments in various multilinear settings.
 
−  In this talk I would like to introduce a brief history of the subject
 
−  and sketch some recent developments, some of these involve my joint
 
−  works with collaborators.
 
   
−  ===Mon, January 13: Yi Wang (Stanford)===
 +  Title: A structure theory for spaces with lower Ricci curvature bounds. 
   
−  ''Isoperimetric Inequality and Qcurvature''
 +  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. 
   
−  A wellknown question in differential geometry is to prove the
 
−  isoperimetric inequality under intrinsic curvature conditions. In
 
−  dimension 2, the isoperimetric inequality is controlled by the integral of
 
−  the positive part of the Gaussian curvature. In my recent work, I prove
 
−  that on simply connected conformally flat manifolds of higher dimensions,
 
−  the role of the Gaussian curvature can be replaced by the Branson's
 
−  Qcurvature. The isoperimetric inequality is valid if the integral of the
 
−  Qcurvature is below a sharp threshold. Moreover, the isoperimetric
 
−  constant depends only on the integrals of the Qcurvature. The proof
 
−  relies on the theory of $A_p$ weights in harmonic analysis.
 
   
−  ===January 15: Wei Xiang (University of Oxford)===  +  == Past Colloquia == 
−   
−  ''Conservation Laws and Shock Waves''
 
−   
−  The study of continuum physics gave birth to the theory of quasilinear
 
−  systems in divergence form, commonly called conservation laws. In this
 
−  talk, conservation laws, the Euler equations, and the definition of the
 
−  corresponding weak solutions will be introduced first. Then a short history
 
−  of the studying of conservation laws and shock waves will be given. Finally
 
−  I would like to present two of our current research projects. One is on the
 
−  mathematical analysis of shock diffraction by convex cornered wedges, and
 
−  the other one is on the validation of weakly nonlinear geometric optics for
 
−  entropy solutions of nonlinear hyperbolic systems of conservation laws.
 
−   
−  Fri, Jan 17, 2:25PM, VV901 Adrianna Gillman (Dartmouth) Fast direct solvers for linear partial differential equations
 
−   
−  ===Fri, Jan 17: Adrianna Gillman (Dartmouth) ===
 
−  ''Fast direct solvers for linear partial differential equations''
 
−   
−  The cost of solving a large linear system often determines what can and cannot be modeled computationally in many areas of science and engineering. Unlike Gaussian elimination which scales cubically with the respect to the number of unknowns, fast direct solvers construct an inverse of a linear in system with a cost that scales linearly or nearly linearly. The fast direct solvers presented in this talk are designed for the linear systems arising from the discretization of linear partial differential equations. These methods are more robust, versatile and stable than iterative schemes. Since an inverse is computed, additional righthand sides can be processed rapidly. The talk will give the audience a brief introduction to the core ideas, an overview of recent advancements, and it will conclude with a sampling of challenging application examples including the scattering of waves.
 
−   
−  ===Thur, Jan 23: Mykhaylo Shkolnikov (Berkeley) ===
 
−  ''Intertwinings, wave equations and growth models''
 
−   
−  We will discuss a general theory of intertwined diffusion processes of any dimension. Intertwined processes arise in many different contexts in probability theory, most notably in the study of random matrices, random polymers and path decompositions of Brownian motion. Recently, they turned out to be also closely related to hyperbolic partial differential equations, symmetric polynomials and the corresponding random growth models. The talk will be devoted to these recent developments which also shed new light on some beautiful old examples of intertwinings. Based on joint works with Vadim Gorin and Soumik Pal.
 
−   
−   
−  ===Jan 24: Yaniv Plan (Michigan) ===
 
−  ''Lowdimensionality in mathematical signal processing''
 
−   
−  Natural images tend to be compressible, i.e., the amount of information needed to encode an image is small. This conciseness of information  in other words, low dimensionality of the signal  is found throughout a plethora of applications ranging from MRI to quantum state tomography. It is natural to ask: can the number of measurements needed to determine a signal be comparable with the information content? We explore this question under modern models of lowdimensionality and measurement acquisition.
 
−   
−  ===Thur, Jan 30: Urbashi Mitra (USC) ===
 
−  ''Underwater Networks: A Convergence of Communications, Control and Sensing''
 
   
−  The oceans cover 71% of the earth’s surface and represent one of the least explored frontiers, yet the oceans are integral to climate regulation, nutrient production, oil retrieval and transportation. Future scientific and technological efforts to achieve better understanding of oceans and waterrelated applications will rely heavily on our ability to communicate reliably between instruments, vehicles (manned and unmanned), human operators, platforms and sensors of all types. Underwater acoustic communication techniques have not reached the same maturity as those for terrestrial radio communications and present some unique opportunities for new developments in information and communication theories. Key features of underwater acoustic communication channels are examined: slow speed of propagation, significant delay spreads, sparse multipath, timevariation and rangedependent available bandwidth. Another unique feature of underwater networks is that the cost of communication, sensing and control are often comparable resulting in new tradeoffs between these activities. We examine some new results (with implications wider than underwater systems) in channel identifiability, communicating over channels with state and cooperative game theory motivated by the underwater network application.
 +  [[Colloquia/BlankBlank]] 
   
−  ===Feb 7: David Treumann (Boston College) ===
 +  [[Colloquia/Fall2018Fall 2018]] 
−  ''Functoriality, Smith theory, and the Brauer homomorphism''
 
   
−  Smith theory is a technique for relating the mod p homologies of X and of the fixed points of X by an automorphism of order p. I will discuss how, in the setting of locally symmetric spaces, it provides an easy method (no trace formula) for lifting mod p automorphic forms from G^{sigma} to G, where G is an arithmetic group and sigma is an automorphism of G of order p. This lift is compatible with Hecke actions via an analog of the Brauer homomorphism from modular representation theory, and is often compatible with a homomorphism of Lgroups on the Galois side. The talk is based on joint work with Akshay Venkatesh. I hope understanding the talk will require less number theory background than understanding the abstract.
 +  [[Colloquia/Spring2018Spring 2018]] 
   
−  ===Feb 14: Alexander Karp (Columbia Teacher's College) ===
 +  [[Colloquia/Fall2017Fall 2017]] 
−  ''History of Mathematics Education as a Research Field and as Magistra Vitae''
 
   
−  The presentation will be based on the experience of putting together and editing the Handbook
 +  [[Colloquia/Spring2017Spring 2017]] 
−  on the History of Mathematics Education, which will be published by Springer in the near future.
 
−  This volume, which was prepared by a large group of researchers from different countries,
 
−  contains the first systematic account of the history of the development of mathematics education
 
−  in the whole world (and not just in some particular country or region). The editing of such a
 
−  book gave rise to thoughts about the methodology of research in this field, and also about what
 
−  constitutes an object of such research. These are the thoughts that the presenter intends to share
 
−  with his audience. From them, it is natural to pass to an analysis of the current situation and how
 
−  it might develop.
 
   
−  ===Feb 21: Svetlana Jitomirskaya (UCIrvine)===
 +  [[Archived Fall 2016 ColloquiaFall 2016]] 
−  ''Analytic quasiperiodic cocycles''
 
   
−  Analytic quasiperiodic matrix cocycles is a simple dynamical
 +  [[Colloquia/Spring2016Spring 2016]] 
−  system, where analytic and dynamical properties are related in an
 
−  unexpected and remarkable way. We will focus on this relation, leading to
 
−  a new approach to the proof of joint continuity of Lyapunov exponents in
 
−  frequency and cocycle, at irrational frequency, first proved for SL(2,C)
 
−  cocycles in BourgainJitom., 2002. The approach is powerful enough to
 
−  handle singular and multidimensional cocycles, thus establishing the above
 
−  continuity in full generality. This has important consequences including
 
−  a dense open version of BochiViana theorem in this setting, with a
 
−  completely different underlying mechanism of the proof. A large part of
 
−  the talk is a report on a joint work with A. Avila and C. Sadel.
 
   
 +  [[Colloquia/Fall2015Fall 2015]] 
   
−  ===March 28: Michael Lacey (GA Tech) ===
 +  [[Colloquia/Spring2014Spring 2015]] 
−  ''The Two Weight Inequality for the Hilbert Transform''
 
   
−  The individual two weight inequality for the Hilbert transform
 +  [[Colloquia/Fall2014Fall 2014]] 
−  asks for a real variable characterization of those pairs of weights
 
−  (u,v) for which the Hilbert transform H maps L^2(u) to L^2(v).
 
−  This question arises naturally in different settings, most famously
 
−  in work of Sarason. Answering in the positive a deep
 
−  conjecture of NazarovTreilVolberg, the mapping property
 
−  of the Hilbert transform is characterized by a triple of conditions,
 
−  the first being a twoweight Poisson A2 on the pair of weights,
 
−  with a pair of socalled testing inequalities, uniform over all
 
−  intervals. This is the first result of this type for a singular
 
−  integral operator. (Joint work with Sawyer, C.Y. Shen and UriateTuero)
 
   
−  == Past Colloquia ==
 +  [[Colloquia/Spring2014Spring 2014]] 
   
 [[Colloquia/Fall2013Fall 2013]]   [[Colloquia/Fall2013Fall 2013]] 