Authors: Steve Hofmann, José María Martell (ICMAT-CSIC), Svitlana Mayboroda, Tatiana Toro and Zihui Zhao
Source: Geometric and Functional Analysis vol. 31
Date of publication: 8 May 2021
This paper establishes the correspondence between the properties of the solutions of a class of PDEs and the geometry of sets in Euclidean space. The authors settle the question of whether (quantitative) absolute continuity of the elliptic measure with respect to the surface measure and uniform rectifiability of the boundary are equivalent, in an optimal class of divergence form elliptic operators satisfying a suitable Carleson measure condition in uniform domains with Ahlfors regular boundaries. The result can be viewed as a quantitative analogue of the Wiener criterion adapted to the singular Lp data case.
The first step is to consider the case in which the desired Carleson measure condition on the coefficients holds with sufficiently small constant, using a novel application of techniques developed in geometric measure theory. Then, they establish the final result, that is, the “large constant case”. The key elements are a powerful extrapolation argument, which provides a general pathway to self-improve scale-invariant small constant estimates, and a new mechanism to transfer quantitative absolute continuity of elliptic measure between a domain and its subdomains.