We will discuss new estimates for the size and structure of the nodal set $\{u=0\}$ and the singular set $\{u=|\nabla u|=0\}$ of solutions to parabolic inequalities with parabolic Lipschitz coefficients. In particular, we show that almost all of these sets are covered by regular parabolic Lipschitz graphs, with quantitative control, and that both satisfy parabolic Minkowski bounds depending only on a doubling quantity at a point. Many of these results are new even in the case of the heat equation on $\mathbb{R}^n \times \mathbb{R}$. This is joint work with Max Hallgren and Zilu Ma.

I will discuss various problems related to the study of the incompressible Euler equation. The main questions that we will look at have to do with the construction and classification of steady solutions, their stability properties, and the dynamics of nearby unsteady solutions.

We review some recent results on the problem of reconstructing a variety from its topology.  This includes some recent work with Fanjun Meng and Lingyao Xie.

I will review recent constructions of oligomorphic tensor categories generalizing Deligne's Rep(S_t). Then, I will lean into the model theoretic part of the question. Specifically, I will explain where there are no continuous families like the original Rep(S_t) and where you should look for n-parameter families, i.e., depending on n free variables. Ultimately, these questions are closely related to classes of structures in model theory.

In 1966, Mark Kac asked the famous question “Can one hear the shape of a drum?”
In his article with this question as the title, he translated it into eigenvalue problems for planar domains.
This question highlighted the relationship between eigenvalues and geometry.
One can then ask how eigenvalues are related to the geometry of the boundary.
In this talk, we consider a special type of eigenvalues, called Steklov eigenvalues, that are closely tied to boundary geometry.
We will introduce Steklov eigenvalues and explain their basic background and applications.
Then we will discuss our recent results on inequalities relating Steklov eigenvalues to the boundary area of compact manifolds.