Local Lipschitz continuity for energy integrals with fast growth and lower order terms
Andrea Torricelli
TL;DR
This work establishes local Lipschitz regularity for local minimizers of variational functionals of the form $\mathcal{F}(u)=\int_{\Omega} f(Du)+g(x,u)\,dx$ in the fast-growth regime with $u$-dependence. The authors extend techniques from prior slow-growth results by leveraging a priori gradient estimates and extensions of the Bounded Slope Condition (BSC) via dual structures related to the Fenchel transform $f^*$. They construct smooth, uniformly convex approximants $f_k$ and obtain Lipschitz bounds for the corresponding minimizers on small balls using barrier methods; passing to the limit yields a local minimizer of the original problem that is locally Lipschitz. The results rely on a detailed sequence of estimates, Euler–Lagrange and second variation formulas, and a Sobolev-type iterative scheme, with constants depending on the data and growth exponents. Overall, the paper advances regularity theory for nonstandard growth variational problems with $u$-dependent Lagrangians and has potential applications in elasticity and image processing.
Abstract
We consider integral functionals with fast growth and the lagrangian explicitly depending on $u$. We prove that the local minimizers are locally Lipschitz continuous.
