Special Session 50: 

A characterization of vanishing chord-arc domains by Poisson kernels

Zihui Zhao
University of Chicago
USA
Co-Author(s):    S. Bortz, M. Engelstein, M. Goering, T. Toro
Abstract:
We consider sets of finite perimeter $E \subset \mathbb{R}^n$ which are Ahlfors regular. On one hand, we use singular integrals to connect the Poisson kernels of $\mathbb{R}^n\setminus E$ with the unit outer normal of $E$. On the other hand, we use arguments in geometric measure theory to show that small oscillations of the unit normal implies $E$ is Reifenberg flat. Combined we get a characterization of vanishing chord-arc domains by Poisson kernels, under much weaker assumptions than previous work of Kenig-Toro.