Events and Activities

Explore current and upcoming events and activities happening at the Institute for Advanced Study.

Dec
09
2022

Joint IAS/Princeton/Montreal/Paris/Tel-Aviv Symplectic Geometry Zoominar

Periodic Orbits and Birkhoff Sections of Stable Hamiltonian Structures
Robert Cardona
9:15am|Remote Access

In this talk, we start by reviewing recent results on the dynamics of Reeb vector fields defined by contact forms on three-dimensional manifolds, and then introduce Reeb fields defined by stable Hamiltonian structures. These are more general and...

Dec
09
2022

Probability Seminar

Conformally Invariant Fields out of Brownian Loop Soups
Wei Qian
11:15am|Simonyi 101 and Remote Access

For each central charge $c\in (0,1]$, we construct a conformally invariant field which is a measurable function of the local time field $\mathcal{L}$ of the Brownian loop soup with intensity $c$ and i.i.d. signs given to each cluster. This field is...

Dec
09
2022

Group Theory/Dynamics Talk

How Small Can a Group or a Graph be to Admit a Non-Trivial Poisson Boundary?
1:30pm|Simonyi Hall 101 and Remote Access

We review results about random walks on groups, discussing results and conjectures relating critical constant for recurrence/transience, growth and Poisson boundary.

Much less is known about behavior of random walks on Schreier graphs. Since any...

Dec
12
2022

Computer Science/Discrete Mathematics Seminar I

Optimization-Friendly Generic Mechanisms Without Money
11:15am|Simonyi 101 and Remote Access

Our goal is to develop a generic framework for converting modern gradient-descent based optimization algorithms into mechanisms where inputs come from self-interested agents.

We focus on aggregating preferences from n players in a context without...

Dec
12
2022

Members' Colloquium

Varieties of Markoff Type: Arithmetic, Combinatorics, Dynamics
2:00pm|Simonyi Hall 101 and Remote Access - see Zoom link below

The Markoff equation $x^2+y^2+z^2=3xyz$, which arose in his spectacular thesis (1879), is ubiquitous in a tremendous variety of contexts. After reviewing some of these, we will discuss (briefly) asymptotics of integer points, and (in some detail)...

Dec
13
2022

Computer Science/Discrete Mathematics Seminar II

A Characterization of Multiclass Learnability
Nataly Brukhim
10:30am|Simonyi Hall 101 and Remote Access

A seminal result in learning theory characterizes the PAC learnability of binary classes through the VC dimension. Extending this characterization to the general multiclass setting has been open since the late 1980s.

We resolve this problem by...

Dec
13
2022

Special Year Research Seminar

Toward Classifying Reducts of the Complex Field
Chieu-Minh Tran
4:00pm|Simonyi 101 and Remote Access

We discuss some recent progress on the model-theoretic problem of classifying the reducts of the complex field (with named parameters and up to interdefinability). The tools we use include Castle’s recent solution of the Restricted Trichotomy...

Dec
14
2022

Analysis & Mathematical Physics

Additive Energy of Regular Measures in One and Higher Dimensions, and the Fractal Uncertainty Principle
3:00pm|Simonyi 101 and Remote Access

We obtain new bounds on the additive energy of (Ahlfors-David type) regular measures in both one and higher dimensions, which implies expansion results for sums and products of the associated regular sets, as well as more general nonlinear functions...