#07-03:

We Study an economy where a collection of individual goods are sold to a set of buyers who want to buy at most one good. We characterize the set of Walrasian equilibirium price vectors in such an economy using sets of overdemanded and underdemanded goods. Further, we give characterizations for the minimum and the maximum Walrasian equilibrium price vectors of this economy. Using our characterizations, we give a sufficient set of rules that generates a broad class of ascending and descending auctions in which truthful bidding is an ex post Nash equilibrium.