IMPLEMENTATION VIA NASH EQUILIBRIA

This paper is concerned with a problem of implementation of a given social choice correspondence (SCC). We introduce an essential monotonicity condition and show that any implementable SCC satisfies this condition. Conversely, in a case of three or more participants any essentially monotone SCC is implementable. In a case of two participants the essential monotonicity condition must be completed by a requirement that the SCC is close to an individually rational correspondence.