A doubly nonlinear elliptic problem with variable exponents, homogeneous Neumann conditions and generalized logistic source

TL;DR

This paper establishes existence and uniqueness for a complex doubly nonlinear elliptic problem with variable exponents and Neumann conditions, using minimal assumptions and detailed proofs to facilitate solving related parabolic equations.

Contribution

It introduces a novel approach that relaxes the typical Lipschitz condition on the source term by leveraging the continuity of Nemytskii operators between variable exponent Lebesgue spaces.

Findings

Proved existence of solutions under weak assumptions.

Established uniqueness results for the elliptic problem.

Provided detailed proofs to support the theoretical framework.

Abstract

The aim of this work is to prove existence and uniqueness results for a doubly nonlinear elliptic problem that is essential for solving the associated parabolic problem using Rothe's method (discretizing time). We work under very weak assumptions, dropping the commonly used condition that the source term is locally Lipschitz, which appears frequently in the literature. Instead, we rely on the continuity of the Nemytskii operator between two Lebesgue spaces with variable exponents. All results presented here are proved in full detail, which makes the article lengthy.