Geometric Analysis and Topology Seminar

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Isoperimetric problems in curved spaces and applications

Speaker: Gioacchino Antonelli, Courant Institute

Location: Warren Weaver Hall 512

Date: Friday, October 11, 2024, 11 a.m.

Synopsis:

In this talk, I shall discuss two results that show how the isoperimetric structure of a space is connected to its geometry.

First, I will show a sharp concavity property of the isoperimetric profile of manifolds with Ricci lower bounds. Although the statement is set in the smooth context, its proof relies on tools from non-smooth geometry that have been developed in recent years. I will explain how this concavity result interplays with the existence, non-existence, and uniqueness of isoperimetric regions in spaces with lower curvature bounds.

Next, I will present a sharp and rigid generalization of the Bishop-Gromov volume comparison theorem. The proof of this result builds on a concavity property of an unequally weighted isoperimetric profile on the manifold, similar to the one mentioned above. Time permitting, I will discuss how this volume estimate has been recently used by L. Mazet, following contributions by O. Chodosh, C. Li, P. Minter, and D. Stryker, to settle a well-known open problem: the stable Bernstein problem in R^n, with n<=6.