Lipschitz regularity of minimizers of variational integrals with variable exponents

Abstract

In this paper we prove the Lipschitz regularity for local minimizers of convex variational integrals of the form \[ \mathfrak{F}( v, Ω)= \int_Ω \! F(x, Dv(x)) \, dx, \] where, for $n>2$ and $N\ge 1$, $\Omega$ is a bounded open set in ${\mathbb{R}}^n$, $u\in W^{1,1}(\Omega ,{\mathbb{R}}^N)$ and the energy density $F:\Omega \times {\mathbb{R}}^{N\times n}\to \mathbb{R}$ satisfies the so called variable growth conditions. The main novelty of the paper is that we assume an almost critical regularity in the Orlicz Sobolev setting for the energy density as a function of the $x$ variable.