The implementation problem is the problem of designing a mechanism (game form) such that the equilibrium outcomes satisfy a criterion of social optimality embodied in a social choice rule. If a mechanism has the property that, in each possible state of the world, the set of equilibrium outcomes...

This paper presents a laboratory experiment to measure the effect of group membership on individual behavior in modified dictator games. The results suggest that this effect is influenced by the degree of group membership saliency. A within-subject design is employed: in stage 1, each subject...

In a market with indivisibilities, Roth and Postlewaite (1977) show that the (weak) core can suffer from instability problems, in the sense that groups of individuals might upset the equilibrium by recontracting among themselves. By contrast, the strong core is stable. Following the seminal...

This paper studies coalitional strategy-proofness of social choice correspondences that map preference profiles into sets of alternatives. In particular, we focus on the Pareto rule, which associates the set of Pareto optimal alternatives with each preference profile, and examine whether or not...

In several situations agents need to be assigned to activities on basis of their preferences, and each agent can take part in at most one activity. Often, the preferences of the agents do not depend only on the activity itself but also on the number of participants in the respective activity. In...

We study a social choice model with partially honest agents, and we show that strategy-proofness is a necessary and sufficient condition to achieve secure implementation. This result provides a behavioral foundation for the rectangularity property; and it offers as a by-product a revelation...

The revelation principle is a fundamental theorem in many economics fields. In this paper, we construct a simple labor model to show that a social choice function which can be implemented costly in Bayesian Nash equilibrium may not be truthfully implementable. The key point is the strategy cost...

In this paper we provide sufficient conditions for a social choice rule to be implementable in strong Nash equilibrium in the presence of partially honest agents, that is, agents who break ties in favor of a truthful message when they face indifference between outcomes. In this way, we achieve a...

We consider collective decision problems where some agents have private information about alternatives and others don't. Voting takes place under strategy-proof rules. Prior to voting, informed agents may or may not disclose their private information, thus eventually influencing the preferences...