Any function from a non-empty polytope into itself that is locally gross direction preserving is shown to have the fixed point property. Brouwer's fixed point theorem for continuous functions is a special case. We discuss the application of the result in the area of non-cooperative game theory.

In this paper which will appear as a chapter in the Handbook ofGeneralized Convexity we discuss the basic ideas ofconvex and quasiconvex analysis in finite dimensional Euclideanspaces. To illustrate the usefulness of this branchof mathematics also applications to optimization theory...