We thank David Pérez-Castrillo, Alvin Roth and an anonimous referee for helpful comments. Financial support from DGICYT (PB92-0590) and CIRIT (GRQ93-2044) AbstractIn the standard two-sided matching models, agents on one side of the market (the institutions) can each be matched to a set of agents (the individuals) on the other side of the market, and the individuals only have preferences de…ned over institutions to which they can be matched. We explicitly study the consequences for stability when the composition of one's coworkers or colleagues can a¤ect the preferences over institutions. Journal of Economic Literature Classi…cation Number: J41.3

No abstract

JEL Classification: C78, D81, J44.

The paper proposes an algorithm to compute the full set of many-to-many stable matchings when agents have substitutable preferences. The algorithm starts by calculating the two optimal stable matchings using the deferred-acceptance algorithm. Then, it computes each remaining stable matching as the firm-optimal stable matching corresponding to a new preference profile which is obtained after modifying the preferences of a previously identified sequence of firms.

Strategy-proof social choice functions are characterized for societies where the space of alternatives is any full dimensional compact subset of a Euclidean space and all voters have generalized single-peaked preferences. Our results build upon and extend those obtained for cartesian product ranges by Border and Jordan (1983). By admitting a large set of non-cartesian ranges, we give a partial answer to the major open question left unresolved in this pioneering article. We prove that our class is composed by generalized median voter schemes which satisfy an additional condition, called the intersection property (Barberà, Massó, and Neme (1997)). Journal of Economic Literature Classi…cation Number: D71.The paper was partially written while Shigehiro Serizawa was fellow of the Canon Foundation in the Universitat Autònoma de Barcelona. We thank Dolors Berga and two anonymous referees for helpful comments. We also thank Judith Panadés for her computer assistance.