Laan, Gerard van der; Talman, Dolf; Yang, Zaifu - Tinbergen Institute - 2002
It is well known that an upper semi-continuous compact- and convex-valued mapping fi from a nonempty compact and convex set X to the Euclidean space of which X is a subset has at least one stationary point, being a point in X at which the image fi(x) has a nonempty intersection with the normal...