Higher-order pseudoconvex functions

Abstract

In terms of n-th order Dini directional derivative with n positive integer we define n-pseudoconvex functions being a generalization of the usual pseudoconvex functions. Again with the n-th order Dini derivative we define n-stationary points, and prove that a point x 0 is a global minimizer of a n-pseudoconvex function f if and only if x 0 is a n-stationary point of f. Our main result is the following. A radially continuous function f defined on a radially open convex set in a real linear space is n-pseudoconvex if and only if f is quasiconvex function and any n-stationary point is a global minimizer. This statement generalizes the results of Crouzeix, Ferland, Math. Program. 23 (1982), 193-205, and Komlósi, Math. Program. 26 (1983), 232-237. We study also other aspects of the n-pseudoconvex functions, for instance their relations to variational inequalities. © 2006 Springer-Verlag Berlin Heidelberg.