The management of natural commons is typically subject to threshold effects: past a certain agregate consumption level, the benefits of the commons will be lost for everybody. As dealing with the global climate illustrates, moreover, it is often impossible to locate an actual threshold with...

A social choice correspondence (SCC) is virtually implementable if it is E-close (in the probability simplex) to some (exactly) implementable correspondence. Abreu and Sen (1991) proved that, without restriction on the set of alternatives receiving strictly positive probability at equilibrium,...

Consider exchange economies in which preferences are continuous, convex and strongly monotonic. It is well known that the Walrasian correspondence is not Nash implementable. Maskin monotonicity (Maskin, 1999) is violated for allocations at the boundary of the feasible set. We derive an...

We study manipulability of multi-valued solutions in fair allocation of homogeneous indivisible objects with monetary transfers. We show that the no-envy solution satisfies some extension of strategy-proofness to multi-valued solutions. Since no-envy implies Pareto efficiency in this literature,...

Consider the problem of exact Nash implementation of social choice correspondences. Define a mechanism in which the planner can randomize on alternatives out of equilibrium while pure alternatives are always chosen in equilibrium. We call such a game form a lottery mechanism. When preferences...

Consider a class of exchange economies in which preferences are continuous, convex and strongly monotonic. It is well known that the Walrasian correspondence defined over this class violates Maskin Monotonicity (Maskin, 1999) and is thus not Nash implementable. However, contrary to a result in...

We construct an elementary mechanism (Dutta-Sen-Vohra, 1995) that Nash implements the Constrained Walrasian correspondence. We extend it to incomplete and non-exclusive information economies by enlarging the message space of agents. We characterize the set of Bayesian equilibrium outcomes of the...

We study a strategic model of community formation on networks. Starting from a seed community member, the process of community formation is sequential, with infinitely-patient and forward-looking agents making strategic offers to their neighbors. Each agent makes an irreversible binary choice,...

A collective decision problem is described by a set of agents, a profile of single-peaked preferences over the real line and a number k of public facilities to be located. We consider public facilities that do not suffer from congestion and are non-excludable. We provide a characterization of...

An allocation rule is securely implementable if it is strategy-proof and has no "bad" Nash equilibrium in its associated direct revelation game [Saijo, T., Sjöström, T., Yamato, T., 2007. Secure implementation. Theoretical Econ. 2, 203-229. Original work published in RIETI Discussion Paper...