A Gamma convergence approach to the critical Sobolev embedding in variable exponent spaces

Abstract

In this paper, we study the critical Sobolev embeddings $W^{1,p(x)}(\Omega )\subset L^{p^{\ast }(x)}(\Omega )$ for variable exponent Sobolev spaces from the point of view of the $\Gamma$-convergence. More precisely we determine the $\Gamma$-limit of subcritical approximation of the best constant associated with this embedding. As an application we provide a sufficient condition for the existence of extremals for the best constant.