Elliptic problems with lack of compactness via a new fixed point theorem

AbstractThis paper provides a new fixed point theorem for increasing self-mappings G:B→B of a closed ball B⊂X, where X is a Banach semilattice which is reflexive or has a weakly fully regular order cone X+. By means of this fixed point theorem, we are able to establish existence results of elliptic problems with lack of compactness