Preprint A591/2008
An existence result for equilibrium problems with some surjectivity consequences
Wilfredo Sosa | Iusem, Alfredo N. | Kassay, Gabor
Keywords: Equilibirum problems | Minty's theorem
We present conditions for existence of equilibrium problems, which are sufficient in the finite dimensional case, without making any monotonicity assumptions on the underlying bifunction. As a consequence we prove surjectivity of set-valued operators of the form T + aI, with a > 0, where T satisfies a property weaker than monotonicity, which we call pre-monotonicity. We study next the notion of maximal pre-monotonicity. Finally, we adapt our conditions for non-convex optimization problems, obtaining as a by-prodcut a new proof of Frank-Wolfe's Theorem.