# Past Events

A nodal domain of a Laplacian eigenvector of a graph is a maximal connected component where it does not change sign. Sparse random regular graphs have been proposed as discrete toy models of "quantum chaos", and it has accordingly been conjectured by Y. Elon and experimentally observed by Dekel…

We prove the Multiplicity One Conjecture for mean curvature flows of surfaces in R^3. Specifically, we show that any blow-up limit of such mean curvature flows has multiplicity one. This has several applications. First, combining our work with results of Brendle and Choi-Haslhofer-Hershkovits-…

Continuing from last week, we cover Chapter 1 of ‘Semiclassical Analysis’ by Guillemin and Sternberg. We are interested in solving a hyperbolic linear partial differential equation involving a time variable. We reduce it to an ‘eikonal equation’, which we can solve locally by finding a…

I will report on my joint work in progress with Lue Pan which proves that the part of the rational p-adic completed cohomology of a general Shimura variety that is locally analytic with "sufficiently regular" infinitesimal weights is concentrated in the middle degree. I will begin with some…

*Abstract:* In recent years several groups of authors introduced various invariants that are based on Lagrangian Floer homology of a symmetric product of a symplectic manifold. In this talk, I will introduce Heegaard Floer symplectic cohomology (HFSH), an invariant of a Liouville domain M…

It turns out you can take the determinant of some linear operators between infinite dimensional spaces (whoa). It turns out the Laplacian on a surface is one of those operators, and the determinant measures something geometric about the underlying space (Whoa!). It turns out that you can…

Abstract: This quarter, we've explored the empirical distribution of the eigenvalues for general Wigner matrices, showing convergence in distribution to the semicircle law for Hermitian matrices. As Christian described, the special case with Gaussian entries allows us to say more and get an…

A system of linear equations is Sidorenko over F_p if any subset of F_p^n contains at least as many solutions to it as a random set of the same density, asymptotically as n->infty. A system of linear equations is common over F_p if any 2-coloring of F_p^n gives at least as many monochromatic…

Abstract: In 1970, Erdos and Sarkozy wrote a joint paper studying sequences of integers a1 < a2 < . . . having what they called property P, meaning that no a_i divides the sum of two larger a_j , a_k. In the paper, it was stated that the authors believed that a subset A ⊂ [n]…