This paper studies repeated implementation of social choice functions in environments with complete information and changing preferences. We introduce the condition of dynamic monotonicity and show that it is necessary for repeated implementation in finite as well as infinite horizon problems....

We consider the implementation problem with at least three agents. We study double implementability of social choice correspondences in Nash equilibria and undominated Nash equilibria. We prove that “DZ-invariance,” “weak no-veto-power,” and “unanimity” together are sufficient for...

We characterize the sharing rule that achieves efficiency in a contribution mechanism when agents are heterogeneous. This rule is not the one that was found by Sen when agents are identical. We also show that for a large class of sharing rules if Nash equilibrium yields efficient allocations,...

We study the repeated implementation of social choice functions in environments with complete information and changing preferences. We de?ne dynamic mono- tonicity, a natural but nontrivial dynamic extension of Maskin monotonicity, and show that it is necessary and almost suf?cient for repeated...

Noting that a full characterization of Nash-implementation is given using a canonical-mechanism and Maskin's theorem (Maskin, 1999) is shown using a mechanism with Saijo's type of strategy space reduction (Saijo, 1988), this paper fully characterizes the class of Nash-implementable social choice...

This paper considers the object allocation problem introduced by Shapley and Scarf (1974). We study secure implementation (Saijo, Sjöström, and Yamato, 2007), that is, double implementation in dominant strategy and Nash equilibria. We prove that (i) an individually rational solution is...

We consider the problem of allocating infinitely divisible commodities among a group of agents. Especially, we focus on the case where there are several commodities to be allocated, and agents have continuous, strictly convex, and separable preferences. In this paper, we establish that the...

This paper studies the application of the notion of secure implementation (Cason, Saijo, Sj¨ostr¨om, and Yamato, 2006; Saijo, Sj¨ostr¨om, and Yamato, 2007) to the problem of allocating indivisible objects with monetary transfers. We propose a new domain-richness condition, termed as minimal...

We study international free-riding-proof coalitions to solve trans-boundary environmental problems such as global warming. We show that the free-riding problem is rather serious so that a free-riding-proof coalition can consist of only a small number of countries. In the optimal coalitional...

Condorcet domains are sets of linear orders with the property that, whenever the preferences of all voters of a society belong to this set, their majority relation has no cycles. We observe that, without loss of generality, every such domain can be assumed to be closed in the sense that it...