We study the implementation of social choice rules in environments with externalities. We prove the impossibility of implementing efficient and α-individually rational rules in dominant strategies. We prove that the α-core is implementable in Nash equilibrium under mild restrictions and it is...

We study the implementability of stable correspondences in marriage markets with externalities. We prove that, contrary to what happens in markets without externalities, no stable revelation mechanism makes a dominant strategy for the agents on one side of the market to reveal their preferences....

Sasaki and Toda (1996) claim that, in marriage markets with externalities, the stable set and the core are not equal, differently to what happen in marriage markets without externalities. However, the example that proves this claim has an error. By proposing an alternative example we prove that...

We study coalition formation problems with general externalities. We prove that if expectations are not prudent a stable coalitions structure can fail to exist. Under prudent expectations a stable coalition structure exists if the set of admissible coalitions is single-lapping. This assumption...