Stable International Environmental Agreements: An Analytical Approach

In this paper we examine the formation of International Environmental Agreements (IEAs). We provide an analytical treatment of the main model used in the literature and offer a formal solution of it (which has not been available so far), while we clarify some misconceptions that exist in the literature. We find that the unique stable IEA consist of either two, three or four signatories if the number of countries is greater than or equal to 5. Furthermore, we show that the welfare of the signatories of a stable IEA is very close to its lowest level vs the welfare of signatories of other non-stable IEAs. While in our model countries' choice variable is emissions, we extend our results to the case where the choice variable is abatement efforts.International Environmental Agreements, Coalition Formation

Stable International Environmental Agreements: An Analytical Approach

In this paper we examine the formation of International Environmental Agreements (IEAs). We show that the welfare of the signatories does not increase monotonically with respect to the number of signatories. We provide an analytical solution of the leadership model. In particular, we find that the unique stable IEA consist of either two, three or four signatories if the number of countries is greater than 4. Furthermore, we show that the welfare of the signatories is almost at its lowest level when the IEA is stable. While in our model countries’ choice variable is emissions, we extend our results to the case where the choice variable is abatement efforts.

Merger Performance under Uncertain Efficiency Gains

In view of the uncertainty over the ability of merging firms to achieve efficiency gains, we model the post-merger situation as a Cournot oligopoly wherein the outsiders face uncertainty about the merged entity’s final cost. At the Bayesian equilibrium, a bilateral merger is profitable provided that non-merged firms sufficiently believe that the merger will generate large enough efficiency gains, even if ex post none actually materialize. The effects of the merger on market performance are shown to follow similar threshold rules. The findings are broadly consistent with stylized facts, and provide a rationalization for an efficiency consideration in merger policy.Horizontal merger, Bayesian Cournot equilibrium, Efficiency gains, Market performance

Random paths to stability in the roommate problem

This paper studies whether a sequence of myopic blockings leads to a stable matching in the roommate problem. We prove that if a stable matching exists and preferences are strict, then for any unstable matching, there exists a finite sequence of successive myopic blockings leading to a stable matching. This implies that, starting from any unstable matching, the process of allowing a randomly chosen blocking pair to form converges to a stable matching with probability one. This result generalizes those of Roth and Vande Vate (1990) and Chung (2000) under strict preferences

Sharing the surplus in games with externalities within and across issues

We consider environments in which agents can cooperate on multiple issues and externalities are present both within and across issues. We propose a way to extend (Shapley) values that have been put forward to deal with externalities within issues to games where there are externalities within and across issues. We characterize our proposal through axioms that extend the Shapley axioms to our more general environment.externalities, cooperative game theory, Shapley value, linked issues.

Sharing the surplus in games with externalities within and across issues

We consider environments in which agents can cooperate on multiple issues and externalities are present both within and across issues. We propose a way to extend (Shapley) values that have been put forward to deal with externalities within issues to games where there are externalities within and across issues. We characterize our proposal through axioms that extend the Shapley axioms to our more general environment