Boundary behavior of solutions to fractional $p$-Laplacian equation
Alireza Ataei
TL;DR
The paper investigates boundary behavior for solutions to the nonlocal nonlinear equation $(-\Delta_p)^s u=f$ on bounded domains. It develops a generalized Hopf's lemma and a global boundary Harnack principle using Wiener regularity, the torsion function $u_{\text{tor}}$, and viscosity-weak formulations, and extends Wiener criteria to nonzero right-hand sides via perturbation. A central contribution is establishing the isolation of the first $(s,p)$-eigenvalue $\Lambda_{p,q}$ under Wiener regularity (with a noted exception when $q=p$). These results deepen the understanding of boundary regularity and spectral properties for fractional $p$-Laplacians and have implications for the qualitative behavior of nonlocal nonlinear elliptic equations.
Abstract
In this work, a generalized Hopf's lemma and a global boundary Harnack inequality are proved for solutions to fractional $p$-Laplacian equations. Then, the isolation of the first $(s,p)$-eigenvalue is shown in bounded open sets satisfying the Wiener criterion.
