August 1994 AbstractFor a simple economic model of transfrontier pollution, widely used in theoretical studies of international treaties bearing on joint abatement, we exhibit in this paper a scheme for sharing national abatement costs, through international financial transfers, which is inspired by a very classical solution concept offered in the theory of cooperative games, namely the "core" of a game. The scheme has the following properties: (i) total damage and abatement costs in all countries are minimized (optimality property), and (ii) no "coalition", i.e. subset, of countries can achieve lower such total costs for its members by taking another course of action in terms of emissions and/or transfers, under some reasonable assumption as to the reactions of those not in the coalition (core property).

When environmental externalities are international-i..e. transfrontier-they most often are multilateral and embody public good characteristics. Improving upon inefficient laissez-faire equilibria requires voluntary cooperation for which the game-theoretic core concept provides optimal outcomes that have interesting properties against free riding.To define the core, however, the characteristic function of the game associated with the economy (which specifies the payoff achievable by each possible coalition of playershere, the countries) must also specify in each case the behavior of the players which are not members of the coalition. This has been for a long time a major unsolved problem in the theory of the core of economies with many producers of a public good.Among the several assumptions that can be made in this respect, a plausible one is defined in this paper, for which it is then shown that the core is nonempty. The proof is constructive in the sense that it exhibits a solution (i.e., an explicit coordinated abatement policy) that has the desired property of nondomination by any proper coalition of countries, given the assumed behavior of the other countries.

This paper develops a general approach to characterizing optimal income tax and enforcement schemes. Our analysis clarifies the nature of the interplay between tax rates, audit probabilities and penalties for misreporting. In particular, it is shown that for a variety of objective functions for the principal the optimal tax schedule is in general concave (at least weakly) and monotonic; the marginal tax rates determine the audit probabilities; and less harsh penalties lead to higher enforcement costs. Our results imply that there exists a tradeoff between equity and efficiency considerations in the enforcement context which is similar to that in the moral hazard context for tax policy.

When environmental externalities are international-i..e. transfrontier-they most often are multilateral and embody public good characteristics. Improving upon inefficient laissez-faire equilibria requires voluntary cooperation for which the game-theoretic core concept provides optimal outcomes that have interesting properties against free riding.To define the core, however, the characteristic function of the game associated with the economy (which specifies the payoff achievable by each possible coalition of playershere, the countries) must also specify in each case the behavior of the players which are not members of the coalition. This has been for a long time a major unsolved problem in the theory of the core of economies with many producers of a public good.Among the several assumptions that can be made in this respect, a plausible one is defined in this paper, for which it is then shown that the core is nonempty. The proof is constructive in the sense that it exhibits a solution (i.e., an explicit coordinated abatement policy) that has the desired property of nondomination by any proper coalition of countries, given the assumed behavior of the other countries.

General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.-Users may download and print one copy of any publication from the public portal for the purpose of private study or research-You may not further distribute the material or use it for any profit-making activity or commercial gain-You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright, please contact us providing details, and we will remove access to the work immediately and investigate your claim.