Seminars Sorted by Series

Members' Colloquium

Mar
10
2025

Members' Colloquium

Erd\H{o}s Unit Distance Problem and Graph Rigidity
1:00pm|Simonyi 101 and Remote Access

Erd\H{o}s unit distance problem asks the following: Let $P$ be a set of $n$ distinct points in the plane, and let $U(P)$ denote the number of pairs of points in $P$ that are at distance 1. How large can $U(P)$ be? In 1946, Erd\H{o}s showed that for...

Mar
17
2025

Members' Colloquium

Buildings, Galleries and Beyond
Petra Schwer
1:00pm|Simonyi 101 and Remote Access

Originally introduced as analogs of symmetric spaces for  groups over non-archimedian fields buildings have proven useful in various areas by now. In this talk I will introduce (Bruhat-Tits) buildings,  combinatorial toolkits to study them and their...

Mar
24
2025

Members' Colloquium

The Mathematical Legacy of Hel Braun
1:00pm|Simonyi 101 and Remote Access

Hel Braun (IAS member 1947-1948) was a mathematician who introduced approaches that continue to impact research today.  Braun's research contributions lie in three areas: classical number theory problems about integers, modular and automorphic forms...

Mar
31
2025

Members' Colloquium

Selmer Groups and Hilbert's Tenth Problem
1:00pm|Simonyi 101 and Remote Access

Selmer groups are a cohomological tool used to reduce the task of finding solutions of certain diophantine equations to easier field and modular arithmetic. I'll explain how this works in down to earth terms and give some concrete applications...

Apr
07
2025

Members' Colloquium

Barcodes in Topology and Analysis
1:00pm|Simonyi 101 and Remote Access

Persistence modules and their associated barcodes were intensively studied since the early 2000s with a view towards applied mathematics. Recently they have also found numerous applications in pure mathematics. We will discuss a few examples from...

Sep
22
2025

Members' Colloquium

Unlikely Intersections and Connections to Geometry
1:30pm|Wolfensohn Hall and Remote Access

The field of unlikely Intersections presents a robust paradigm for problems in which several subjects intermingle: arithmetic, o-minimality, and hodge theory. The goal of this talk will be to introduce some of those connections. My aim is to...

Oct
06
2025

Members' Colloquium

Billiards in Polygons
1:30pm|Simonyi 101 and Remote Access

Consider a point mass traveling in a polygon. It travels in a straight line, with constant speed, until it hits a side, at which point it obeys the rules of elastic collision. What can we say about this? When all the angles of the polygon are...

Oct
20
2025

Members' Colloquium

Random Perturbation of Toeplitz Matrices
1:30pm|Simonyi 101 and Remote Access

In 1947 John Von Neumann and Herman Goldstine, while developing the IAS computing machines, wrote a seminal paper on numerical errors in matrix computations. They suggested modeling the "computing noise" (coming from rounding errors, transcendental...

Oct
27
2025

Members' Colloquium

O-Minimality and Rational Numbers
1:30pm|Simonyi 101 and Remote Access

I'll give a brief introduction to o-minimality and how it can be used to prove asymptotic estimates for the number of rational points in definable sets. I'll then show how problems from various areas of mathematics can be reformulated as questions...

Nov
03
2025

Members' Colloquium

A Dogged Pursuit for Satisfaction
1:30pm|Simonyi 101 and Remote Access

The SAT (Boolean Satisfiability) problem asks whether a given logical formula on $n$ Boolean variables has an assignment of true/false values to its variables that makes the formula true.  The P vs NP question is equivalent to asking whether SAT has...

Nov
10
2025

Members' Colloquium

Categorical Local Langlands Correspondence and Applications
1:30pm|Simonyi 101 and Remote Access

Langlands, inspired by his work on classification of representations of real groups, initiated a program of classifying representations of certain topological groups associated to reductive groups in terms of Langlands parameters. In the recent...

Nov
17
2025

Members' Colloquium

Beyond Worst-Case Analysis in Online Learning
Tim Roughgarden
1:30pm|Simonyi 101 and Remote Access

One of the primary goals of the mathematical analysis of algorithms is to provide guidance about which algorithm is the “best” for solving a given computational problem. Worst-case analysis summarizes the performance profile of an algorithm by its...

Nov
24
2025

Members' Colloquium

Visualizing Ricci Flow
1:30pm|Simonyi 101 and Remote Access

Riemannian metrics are the simplest generalizations of Euclidean geometry to smooth manifolds. The Ricci curvature of a metric measures, in an averaged sense, how the geometry deviates from being flat. The tensor $-2\,\mathrm{Ric}$ can be viewed as...

Dec
01
2025

Members' Colloquium

Mathematical Exploration and Discovery at Scale
1:30pm|Simonyi 101 and Remote Access

Machine learning is transforming mathematical discovery, enabling advances on longstanding open problems. In this talk, I will discuss AlphaEvolve, a general-purpose evolutionary coding agent that uses large language models to autonomously discover...

Dec
08
2025

Members' Colloquium

New Methods in Resolution of Singularities
1:30pm|Simonyi 101 and Remote Access

Since Hironaka's famous resolution of singularities in characteristics zero in 1964, it took about 40 years of intensive work of many mathematicians to simplify the method, describe it using conceptual tools and establish its functoriality. However...

Dec
15
2025

Members' Colloquium

Fundamental Groups of Algebraic Varieties and the Shafarevich Conjecture
1:30pm|Simonyi 101 and Remote Access

The fundamental group $\pi_1(X)$ is an important invariant of a complex algebraic variety X.  Despite its topological nature, it is closely connected to the geometry of many algebraic structures on X.  In this talk I want to discuss two elementary...

Members’ Seminar

Dec
06
2004

Members’ Seminar

Completing the Bernstein Program (A Geometric Conjecture within the Representation Theory of p-adic Groups)
4:00pm|S-101
Jan
31
2005

Members’ Seminar

Approximation algorithms and Grothendieck type inequalities
4:00pm|S-101

I will describe a connection between a classical inequality of Grothendieck and approximation algorithms based on semi-definite programming. The investigation of this connection suggests the definition of a new graph parameter, called the...

Feb
14
2005

Members’ Seminar

Blow up in a 3-D "toy" model for the Euler equations
4:00pm|S-101

We present a 3-D vector dyadic model given in terms of an infinite system of nonlinearly coupled ODE. This toy model is inspired by approximations to the fluid equations studied by Dinaburg and Sinai. The model has structural similarities with the...

Feb
22
2005

Members’ Seminar

A New Characterization of Sobolev Spaces
3:00pm|S-101

This talk is motivated by some recent work of Bourgain- rezis-Mironescu. A few years ago, they introduced an elementary way of defining the Sobolev spaces $W^{1,p}$ without making any use of derivatives. I will present their definition and some...

Mar
14
2005

Members’ Seminar

A Liouville Type Result for some Conformally Invariant Fully Nonlinear Equations
4:00pm|S-101

I will talk about some joint work with Yanyan Li which extended the Liouville type theorem of Caffarelli-Gidas-Spruck's on the Yamabe equation to the fully nonlinear case.

Mar
21
2005

Members’ Seminar

Polynomiality Properties of Type A Weight and Tensor Product Multiplicities
4:00pm|S-101

Kostka numbers and Littlewood-Richardson coefficients appear in the representation theory of complex semisimple Lie algebras of type A, respectively as the multiplicities of weights in irreducible representations, and the multiplicities of...

Mar
28
2005

Members’ Seminar

Exotic Smooth Structures on Rational Surfaces
4:00pm|S-101

Most known smoothable simply connected 4--manifolds admit infinitely many different smooth structures (distinguished, for example, by Seiberg--Witten invariants). There are some 4--manifolds, though, for which the existence of such 'exotic'...

Apr
11
2005

Members’ Seminar

Iterated Integrals and Algebraic Cycles
4:00pm|S-101

It will be on some constructions in the candidate category of mixed Tate Motives constructed by Bloch and Kriz.

Oct
31
2005

Members’ Seminar

Motivic Integration, Constructible Functions, and Stringy Chern Classes
4:00pm|S-101

In this talk I will discuss a joint work with Lupercio, Nevins and Uribe, in which we use motivic integration to give a theory of Chern classes for singular algebraic varieties that is birationally well-behaved (i.e., with a "stringy" flavor). The...

Nov
07
2005

Members’ Seminar

On some Properties of the Nottingham Group
4:00pm|S-101

Let F be a finite field. The Nottingham group N(F) is the group of formal power series \{ t(1+a_1 t + a_2 t^2 + ...): a_i \in F \}or, equivalently, the group of wild automorohisms of the local field F((t)). In spite of such a simple definition, the...

Nov
28
2005

Members’ Seminar

Generalized Teichmueller Spaces
4:00pm|S-101

Classical Teichmueller space parametrizes complex structures on a Riemann surface of genus g>1. Recently several generalized Teichmueller spaces have been defined and studied by very different approaches. Nevertheless, some of the results are...

Jan
30
2006

Members’ Seminar

Universality for Mathematical and Physical Systems
Percy Deift
4:00pm|S-101

All physical systems in equilibrium obey the laws of thermodynamics. In other words, whatever the precise nature of the interaction between the atoms and molecules at the microscopic level, at the macroscopic level, physical systems exhibit...

Feb
13
2006

Members’ Seminar

Random Walks and Equidistribution on Lie Groups
4:00pm|S-101

I will discuss various issues related to the local problem on Lie groups, the asymptotics of the return probablity, and the equidistribution of dense subgroups.

Feb
20
2006

Members’ Seminar

The Deligne-Simpson Problem and Double Affine Hecke Algebras
4:00pm|S-101

Let us fix $m$ conjugacy classes $C_1,\dots,C_m$ inside $GL(n)$. The variety of $m$-tuple of matrices such that: $$X_i\in C_i, \quad i=1,\dots,m mbox{ and } X_1\dots X_m=1.$$ is a solution of the Deligne-Simpson problem. Double affine Hecke algebras...

Mar
13
2006

Members’ Seminar

Multivariable Mahler Measure and Regulators
4:00pm|S-101

The Mahler measure of an n-variable polynomial P is the integral of log|P| over the n-dimensional unit torus T^n with the Haar measure. For one-variable polynomials, this is a natural quantity that appears in different problems such as Lehmer's...