Noritsugu Nakanishi

Noncooperative farsighted stable set in an n-player prisoners’ dilemma

We examine an n-player prisoners’ dilemma game in which only individual deviations are allowed, while coalitional deviations (even non-binding ones) are not, and every player is assumed to be sufficiently farsighted to understand not only the direct outcome of his own deviation but also the ultimate outcome resulting from a chain of subsequent deviations by other players. We show that there exists a unique, noncooperative farsighted stable set (NFSS) and that it supports at least one (partially and/or fully) cooperative outcome, which is individually rational and Pareto-efficient. We provide a sufficient condition for full cooperation. Further, we discuss the relationship between NFSS and other “stable set” concepts such as the (myopic) von Neumann–Morgenstern stable set, Harsanyi (1974)’s strictly stable set, Chwe (1994)’s largest consistent set, and the cooperative farsighted stable set examined by Suzuki and Muto (2005).

Welfare analysis of tariff change with and without international transfers

Abstract We derive necessary-sufficient conditions for the existence of a strictly Pareto-improving tariff reform both with and without changes in international lump-sum transfer of income, in a many-commodity, many-country framework. Then we show that these conditions are equivalent; if a tariff reform with appropriate changes in transfers attains a strict Pareto improvement, then there exists another tariff reform that attains a strict Pareto improvement without such transfers. In the course of this investigation, we find that the ‘Rank Condition’ plays an essential role and also has some interesting economic implications.