Stanford University

Past Events

Wednesday, March 13, 2024
12:00 PM
|
384H
Lexing Ying (Stanford)

This talk discusses the unstructured sparse recovery problems of a general form. The task is to recover the spike locations and weights of an unknown sparse signal from a collection of its unstructured observations. Examples include rational approximation, spectral function estimation, Fourier…

Tuesday, March 12, 2024
4:00 PM
|
383N
Joshua Greene (Boston College)

Given n points and a smooth Jordan curve in the complex plane, what is the minimum degree of a non-constant polynomial which maps all of the points to the curve?  It is easy to bound the degree above by n-1, while if the points are collinear and the curve is an ellipse, then the degree is…

Tuesday, March 12, 2024
4:00 PM
|
384H
Mihaela Ifrim (UC Berkeley, UW-Madison)

Abstract: In this work we prove global well-posedness for the massive Maxwell-Dirac equation in the Lorentz gauge in $\mathbb{R}^{1+3}$, for small and localized initial data, as well as modified scattering for the solutions.  In doing so, we heuristically exploit the close connection…

Tuesday, March 12, 2024
1:00 PM
|
384H
Dhruv Goel (Harvard)

Given a nondegenerate smooth variety X in P^n, let S(X) (resp. T(X)) be the subvariety of the Grassmannian Gr(2, n+1) consisting of secant (resp. tangent) lines to X. I will give closed-form formulae for the classes of S(X) and T(X) in the Chow ring of Gr(2,n+1) in terms of the “higher…

Monday, March 11, 2024
4:00 PM
|
383N
Wenyuan Li (USC)

Generating families (generating functions) for exact Lagrangian or Legendrian submanifolds provides a finite dimensional approach to understanding nonclassical invariants of the submanifolds. Given an exact Lagrangian cobordism between Legendrians in 1-jet bundles, we prove that a generating…

Monday, March 11, 2024
4:00 PM
|
Sequoia 200
Kevin Yang (Harvard)

We will discuss non-Hermitian random matrix models, namely the universality problem for local eigenvalue statistics. The main result is universality in the bulk (i.e., away from the edge of the limiting spectrum) for complex eigenvalues of real non-symmetric matrices with i.i.d. entries. The…

Monday, March 11, 2024
3:45 PM
|
384I
Nathan Chen (Columbia)

The classical question of determining which varieties are rational has led to a huge amount of interest and activity. On the other hand, one can consider a complementary perspective - given a smooth projective variety whose nonrationality is known, how "irrational" is it? I will survey…

Monday, March 11, 2024
2:30 PM
|
384I
John Anderson (Stanford)

In this talk, I will continue to describe aspects of geometric optics, one of the main themes introduced earlier.  I also hope to describe a bit more about how this relates to some interesting properties of hyperbolic PDE.  In particular, I hope to motivate a bit more about why you may…

Monday, March 11, 2024
2:30 PM
|
383N
Konstantin Miagkov (Stanford)

Automorphy lifting theorems establish situations in which Galois representations over \bar{Q_p} are automorphic if their residual representation has an automorphic lift. In 2018, Allen et. al. proved the first automorphy lifting theorem for n-dimensional Galois representations over a CM field…

Monday, March 11, 2024
11:30 AM
|
384H
Judson Kuhrman (Stanford)

An “abstract polyhedron” means, roughly, a graph that “might be the edges and vertices of a polyhedron”.  When can we promote “might be” to “is”? This question is answered by a beautiful theorem about circle packings on the sphere. I will explain the proof of this theorem, as well as some…