Nash implementation of constrained efficient stable matchings under weak priorities

Abstract

In this study, we consider priority-based matching problems in which indifferent priorities are allowed. Although indifferences in priorities are naturally present in practice, it is unknown whether constrained efficient stable matchings are implementable in any strategic solution concept. Therefore, in this study, we show that (1) stable matchings are Nash implementable via a “practical” mechanism and (2) constrained efficient stable matchings are Nash implementable if and only if priorities satisfy the conditions identified by Ehlers and Erdil (2010). These findings immediately imply that efficient and stable matchings are Nash implementable under the same condition.