Existence of Equilibrium Prices for Discontinuous Excess Demand Correspondences

The aim of the paper is to obtain the existence of equilibrium prices in economies where the excess demand correspondences—differently from the usual condition—are not necessarily upper semicontinuous. So, in our setting, we cannot use the Gale-Debreu-Nikaido Lemma. The existence of equilibrium prices is obtained for discontinuous excess demand correspondences which obey to a condition like of the weak axiom of reveled preferences.