Between quasi-convex and convex set-valued mappings Original Research Article

The aim of this paper is to give sufficient conditions for a quasi-convex set-valued mapping to be convex. In particular, we recover several known characterizations of convex real-valued functions, given in terms of quasiconvexity and Jensen-type convexity by Nikodem [1], Behringer [2], and Yang, Teo and Yang [3].