The existence of extremal functions for discrete Sobolev inequalities on lattice graphs
arXiv:2106.15982
Abstract
In this paper, we study the existence of extremal functions of the discrete Sobolev inequality and Hardy-Littlewood-Sobolev inequality on lattice graphs. We introduce the discrete Concentration-Compactness principle, and prove the existence of extremal functions for the best constants in the supercritical cases.
16 pages