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Satoru Takahashi Publications

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Abstract

We provide tight bounds on the rate of convergence of the equilibrium payoff sets for repeated games under both perfect and imperfect public monitoring. The distance between the equilibrium payoff set and its limit vanishes at rate (1 − δ)1/2 under perfect monitoring, and at rate (1 − δ)1/4 under imperfect monitoring. For strictly individually rational payoff vectors, these rates improve to 0 (i.e., all strictly individually rational payoff vectors are exactly achieved as equilibrium payoffs for delta high enough) and (1 − δ)1/2, respectively.

Abstract

This paper characterizes an equilibrium payoff subset for dynamic Bayesian games as discounting vanishes. Monitoring is imperfect, transitions may depend on actions, types may be correlated and values may be interdependent. The focus is on equilibria in which players report truthfully. The characterization generalizes that for repeated games, reducing the analysis to static Bayesian games with transfers. With independent private values, the restriction to truthful equilibria is without loss, except for the punishment level; if players withhold their information during punishment-like phases, a folk theorem obtains.

Abstract

This paper provides a dual characterization of the limit set of perfect public equilibrium payoffs in stochastic games (in particular, repeated games) as the discount factor tends to one. As a first corollary, the folk theorems of Fudenberg, Levine and Maskin (1994), Kandori and Matsushima (1998) and Hörner, Sugaya, Takahashi and Vieille (2011) obtain. As a second corollary, in the context of repeated games, it follows that this limit set of payoffs is a polytope (a bounded polyhedron) when attention is restricted to equilibria in pure strategies. We provide a two-player game in which this limit set is not a polytope when mixed strategies are considered.

Abstract

We consider the efficient allocation of a single good with interdependent values in a quasi-linear environment. We present an approach to modelling interdependent preferences distinguishing between “payoff types” and “belief types” and report a characterization of when the efficient allocation can be partially Bayesian implemented on a finite type space. The characterization can be used to unify a number of sufficient conditions for efficient partial implementation in this classical auction setting.

We report how a canonical language for discussing interdependent types — developed in a more general setting by Bergemann, Morris and Takahashi (2011) — applies in this setting and note by example that this canonical language will not allow us to distinguish some types in the payoff type — belief type language.

Abstract

We study agents whose expected utility preferences are interdependent for informational or psychological reasons. We characterize when two types can be “strategically distinguished” in the sense that they are guaranteed to behave differently in some finite mechanism. We show that two types are strategically distinguishable if and only if they have different hierarchies of interdependent preferences. The same characterization applies for rationalizability, equilibrium, and any interim solution concept in between. Our results generalize and unify results of Abreu and Matsushima (1992), who characterize strategic distinguishability on fixed finite type spaces, and Dekel, Fudenberg, and Morris (2006), (2007), who characterize strategic distinguishability without interdependent preferences.

Abstract

We present an algorithm to compute the set of perfect public equilibrium payoffs as the discount factor tends to one for stochastic games with observable states and public (but not necessarily perfect) monitoring when the limiting set of (long-run players’) equilibrium payoffs is independent of the state. This is the case, for instance, if the Markov chain induced by any Markov strategy profile is irreducible. We then provide conditions under which a folk theorem obtains: if in each state the joint distribution over the public signal and next period’s state satisfies some rank condition, every feasible payoff vector above the minmax payoff is sustained by a perfect public equilibrium with low discounting.