Solutions of the fractional 1-Laplacian: existence, asymptotics and flatness results

Abstract

In this paper, we study the existence of solutions of the equation $(-\Delta {)}_1^{s}u=f$ in a bounded open set with Lipschitz boundary $Ω\subset \Rn$, vanishing on $\Co Ω$, for some given $s\in (0,1)$, and asymptotics as $p\to 1$ of solutions of $(-\Delta {)}_p^{s}u=f$. We obtain existence and convergence by comparing the $L^{\frac{n}{s}}$ norm of $f$ to the sharp fractional Sobolev constant, or, when $f$ is non-negative, the weighted fractional Cheegar constant to $1$ -- in this case, the results are sharp. We further prove that solutions are "flat" on sets of positive Lebesgue measure.

35 pages