Quasi-Harnack inequality

Autor: Ovidiu Savin, Daniela De Silva
Rok vydání: 2021
Předmět:
Zdroj: American Journal of Mathematics. 143:307-331
ISSN: 1080-6377
DOI: 10.1353/ajm.2021.0001
Popis: In this paper we obtain some extensions of the classical Krylov-Safonov Harnack inequality. The novelty is that we consider functions that do not necessarily satisfy an infinitesimal equation but rather exhibit a two-scale behavior. We require that at scale larger than some $r_0>0$ (small) the functions satisfy the comparison principle with a standard family of quadratic polynomials, while at scale $r_0$ they satisfy a Weak Harnack type estimate. We also give several applications of the main result in very different settings such as discrete difference equations, nonlocal equations, homogenization and the quasi-minimal surfaces of Almgren.
Databáze: OpenAIRE