Past Events

Curve graphs are crucial tools for studying mapping class groups of surfaces. However, many basic questions on their geometry remain open. In this talk, we will shed light on the geometry of curve graphs by describing “filtrations” of them by hyperbolic graphs. These filtrations yield quasi-…

Abstract: In this talk, I will present a method to construct nontrivial global solutions to some quasilinear wave equations in three space dimensions. We first present a conditional result. Assuming that a global solution to the geometric reduced system exists and satisfies several well-chosen…

I will discuss joint work with Luya Wang on the other direction of the Donaldson 4-6 problem. Specifically, we show that any two simply-connected symplectic 4-manifolds, whose products with S^2 are deformation equivalent, have the same Gromov-Witten invariants. The proof relies on a…

I will talk about parallelization of sampling algorithms. The main focus of the talk will be a new result, where we show how to speed up sampling from an arbitrary distribution on a product space [q]^n, given oracle access to conditional marginals. Our algorithm takes roughly n^{2/3} polylog(n,…

Scholze has conjectured the existence of the so-called Igusa stacks, which have close relation to Shimura varieties. In my thesis and the joint work in progress with Daniels, van Hoften and Kim, these conjectural stacks are constructed for many interesting classes of Shimura varieties. In this…

Calculus is hard. In most textbooks and calculus classes, the chain rule (f∘g)′(x) = f′(g(x))∘g′(x) is either not proved, or only partially proved. The reason is that the proof requires knowledge of topology not covered in the first two years of university, and most importantly, the result fails…

Abstract: I will introduce the GOE (orthogonal) and GUE (unitary) Gaussian ensembles, which are special Wigner matrices with Gaussian entries leading to nice symmetries. The main result will be the Ginibre formula for the density of the eigenvalues of these ensembles. There are several ways to…

Abstract: I will explain how the  count of algebraic curves in the complex projective plane can be reduced to a solution of a Hamilton-Jacobi equation.

We will describe recent progress, in joint work with Jeck Lim, on the study of sumset estimates in higher dimensions. The basic question we discuss is the following: given a subset A of d-dimensional space and a linear transformation L, how large is the sumset A + LA?