This paper provides necessary and sufficient conditions for fixed-point theorems, minimax inequalities and some related theorems defined on arbitrary topological spaces that may be discrete, continuum, non-compact or non-convex. We establish a single condition, γ-recursive transfer lower...

This paper generalizes two theorems in Campbell and Walker (1990), which is based on weak upper continuity. A new property, called partial upper continuity, is shown to be sufficient for representation and existence of a maximal element. Noting that transfer weak upper continuity (Tian and Zhou,...

We provide the first necessary and su±cient conditions in the literature for the existence of maximal elements in a non-binary choice framework. As an application, the characterization of the existence of maximal elements for acyclic binary relations obtained in Rodriguez-Palmero and...