Let X be a nonempty, compact, convex set in R and let f be an upper semicontinuous mapping from X to the collection of nonempty, compact, convex subsets of R. It is well known that such a mapping has a stationary point on X; i.e., there exists a point X such that its image under f has a nonempty intersection with the normal cone of X at the point. In the case where, for every point in X, it hol...
