A transversal generated by a system of distinct representatives (SDR) for a colection of sets consists of an element from each set (its representative) such that the representative uniquely identifies the set it belongs to. Theorem 1 gives a necessary and sufficient condition that an arbitrary...

A pre-recorded version of Leonid Hurwicz' Prize Lecture was presented on 8 December 2007 at Aula Magna, Stockholm University. The lecture was introduced by Professor Jorgen Weibull, Chairman of the Economics Prize Committee.

This paper obtains finite counterparts of previous results that showed the informational efficiency of the Walrasian mechanism among all mechanisms yielding Pareto-optimal individually rational trades in exchange economies while using a continuum of possible messages. In particular, we develop...