A Bargaining Set Based on External and Internal Stability and Endogenous Coalition Formation

A new bargaining set based on notions of both internal and external stability is developed in the context of endogenous coalition formation.It allows to make an explicit distinction between within-group and outsidegroup deviation options.This type of distinction is not present in current bargaining sets.For the class of weighted majority games, the outcomes in the bargaining set containing a minimal winning coalition are characterized.Furthermore, it is shown that the bargaining set of any homogeneous weighted majority game contains an outcome for which the underlying coalition structure consists of a minimal winning coalition and its complement.The paper also introduces a new class of games called cooperation externalities games.For a symmetric cooperation externalities game conditions are provided such that every outcome in the bargaining set supports the same coalition structure.This coalition structure consists of one coalition of all players with an externality parameter higher than one and a collection of singleton coalitions, one for every player with a cooperation externality parameter lower than oneBargaining set;endogenous colation;formation;internal and external stability

Cooperative Games with Incomplete Information: Some Open Problems

This is a brief survey describing some of the recent progress and open problems in the area of cooperative games with incomplete information. We discuss exchange economies, cooperative Bayesian games with orthogonal coalitions, and issues of cooperation in non-cooperative Bayesian games.#

Cooperative games in strategic form

In this paper we view bargaining and cooperation as an interaction superimposed on a strategic form game. A multistage bargaining procedure for N players, the “proposer commitment” procedure, is presented. It is inspired by Nash’s two-player variable-threat model; a key feature is the commitment to “threats.” We establish links to classical cooperative game theory solutions, such as the Shapley value in the transferable utility case. However, we show that even in standard pure exchange economies the traditional coalitional function may not be adequate when utilities are not transferable.Bargaining, Commitment, Nash variable threat

Cooperation, Stability and Self-Enforcement in International Environmental Agreements: A Conceptual Discussion

In essence, any international environmental agreement (IEA) implies cooperation of a form or another. The paper seeks for logical foundations of this. It first deals with how the need for cooperation derives from the public good aspect of the externalities involved, as well as with where the source of cooperation lies in cooperative game theory. In either case, the quest for efficiency is claimed to be at the root of cooperation. Next, cooperation is considered from the point of view of stability. After recalling the two competing concepts of stability in use in the IEA literature, new insights on the nature of the gamma core in general are given as well as of the Chander-Tulkens solution within the gamma core. Free riding is also evaluated in relation with the alternative forms of stability under scrutiny. Finally, it is asked whether with the often mentioned virtue of “self enforcement” any conceptual gain is achieved, different from what is meant by efficiency and stability. A skeptical answer is offered, as a reply to Barrett’s (2003) attempt at giving the notion a specific content.International Environmental Agreements, Cooperation, Stability, Self-enforcement

Optimal Transfers and Participation Decisions in International Environmental Agreements

The literature on international environmental agreements has recognized the role transfers play in encouraging participation in international environmental agreements (IEAs), but the few results achieved so far are overly specific and do not exploit the full potential of transfers for successful treaty-making. Therefore, in this paper, we develop a framework that enables us to study the role of transfers in a more systematic way. We propose a design for transfers using both internal and external financial resources and making “welfare optimal agreements” self-enforcing. To illustrate the relevance of our transfer scheme for actual treaty-making, we use a well-known integrated assessment model of climate change to show how appropriate transfers may be able to induce almost all countries into signing a self-enforcing climate treaty.Self-enforcing international environmental agreements, Climate policy, Transfers

A Bargaining Set Based on External and Internal Stability and Endogenous Coalition Formation

A new bargaining set based on notions of both internal and external stability is developed in the context of endogenous coalition formation.It allows to make an explicit distinction between within-group and outsidegroup deviation options.This type of distinction is not present in current bargaining sets.For the class of weighted majority games, the outcomes in the bargaining set containing a minimal winning coalition are characterized.Furthermore, it is shown that the bargaining set of any homogeneous weighted majority game contains an outcome for which the underlying coalition structure consists of a minimal winning coalition and its complement.The paper also introduces a new class of games called cooperation externalities games.For a symmetric cooperation externalities game conditions are provided such that every outcome in the bargaining set supports the same coalition structure.This coalition structure consists of one coalition of all players with an externality parameter higher than one and a collection of singleton coalitions, one for every player with a cooperation externality parameter lower than one

The Core of a Normal Form Game

Due to the externalities, in normal form games a deviation changes the payoff of all players inducing a retaliation by the remaining or residual players. The stability of an outcome depends on the expectations potential deviators have about this reaction, but so far no satisfactory theory has been provided. The present paper continues the work of Chander and Tulkens (1997) where deviators consider residual equilibria, but we allow coalitions to form, moreover introduce consistency between the residual solution and the solution of the original game. Optimistic and pessimistic considerations produce a pair of cores. These cores are compared to some existing cooperative concepts such as the gamma- and r-cores and the equilibrium binding agreements. In our final section we discuss the predominance of the grand coalition and suggest a generalisation of the normal form where such a precedence can be removed.externalities, residual game, cohesiveness, partition function