Lipschitz regularity of almost-minimizers in one-phase problems with generalized Orlicz growth
Chiara Leone, Giovanni Scilla, Francesco Solombrino, Anna Verde
TL;DR
We address local Lipschitz regularity for scalar almost-minimizers of Alt-Caffarelli-type functionals with generalized Orlicz growth, capturing nonstandard growth and space-inhomogeneity through $\varphi$.The approach builds a robust non-autonomous Orlicz-Sobolev framework, constructs a regularized $\widetilde{\varphi}$, and uses comparison with $\widetilde{\varphi}$-harmonic replacements together with blow-up arguments to obtain $C^{0,\alpha}$ and $C^{1,\alpha}$-type results away from the free boundary, plus sublinear behavior near the free boundary.Key contributions include a unified Lipschitz regularity theory for almost-minimizers under nonstandard growth (including perturbed Orlicz, variable exponent, and double-phase energies), with a versatile toolkit for autonomous and non-autonomous settings and potential extension to vector-valued problems.The results pave the way for a deeper understanding of free boundary regularity in nonstandard growth settings and provide stable regularity estimates that can inform numerical methods for related phase-field problems.
Abstract
The optimal local Lipschitz regularity for scalar almost-minimizers of Alt-Caffarelli-type functionals $$ \mathcal{F}({v}; Ω) = \int_Ω\varphi(x,\left|\nabla v(x) \right|)+ λχ_{\{{v} >0\}} (x) \, \mathrm{d}x\,, $$ with growth function $\varphi$ a generalized Orlicz function, is established.
