Stability of Climate Coalitions in a Cartel Formation Game

This paper analyses the formation and stability of coalitions to form international environmental agreements. We present and apply the Stability of coalitions model to assess the internal and external stability of all possible coalition structures in a cartel formation game; first under the assumption that no transfers take place and second for a transfer scheme. One important novelty of this paper is the analysis of the incentive structure of twelve regions for all possible combinations of (cartel) coalitions in an empirical setting with asymmetric regions. We show that stable coalitions can emerge only if benefits from global abatement are sufficiently high or if an appropriate transfer scheme is introduced.The authors acknowledge the support of Juan-Carlos Altamirano-Cabrera, Eligius Hendrix, Niels Olieman, Pepijn van Oort, Arjan Ruijs and Hans-Peter Weikard in the analysis. Furthermore, the comments by two anonymous referees are gratefully acknowledged. The usual disclaimer applies.     

Spatial pillage game

A pillage game is a coalitional game as a model of Hobbesian anarchy. The spatial pillage game introduces a spatial feature into the pillage game. Players are located in regions and can travel from one region to another. The players can form a coalition and combine their power only within their destination regions, which limits the exertion of the power of each coalition. Under this spatial restriction, a coalition can pillage less powerful coalitions without any cost. The feasibility of pillages between coalitions determines the dominance relation that defines stable states in which powers among the players are endogenously balanced. With the spatial restriction, the set of stable states changes. However, if the players have forecasting ability, then the set of stable states does not change with the spatial restriction. Core, stable set, and farsighted core are adopted as alternative solution concepts.     

国际环境合作的经济学分析

本文利用现代经济学理论与方法，构筑了一个分析国际环境合作问题的经济学框架。分析的中心是建立一个静态模型来寻求作为一个联盟形态的国际环境合作的内部和外部稳定性条件，主要结论是稳定的国际环境合作是由模型给定的参数内生地决定的。与当前大多数研究的一个重要不同是，我们的模型没有采用通常的减少污染排放这一分析参数，而是选用了更为直接的污染排放量这一指标。在运用联盟理论对两类情形即不合作和完全合作进行模型化处理的基础上，本文导出了联盟成员国与非成员国福利水平和污染排放量的若干命题，并建立起国际环境合作稳定性的条件。     

Stable and efficient coalitional networks

We develop a theoretical framework that allows us to study which bilateral links and coalition structures are going to emerge at equilibrium. We define the notion of coalitional network to represent a network and a coalition structure, where the network specifies the nature of the relationship each individual has with her coalition members and with individuals outside her coalition. To predict the coalitional networks that are going to emerge at equilibrium we propose the concepts of strong stability and of contractual stability. Contractual stability imposes that any change made to the coalitional network needs the consent of both the deviating players and their original coalition partners. Requiring the consent of coalition members under the simple majority or unanimity decision rule may help to reconcile stability and efficiency. Moreover, this new framework can provide insights that one cannot obtain if coalition formation and network formation are tackled separately and independently.     

Blockholdings in closely held corporations: An analysis of ownership coalitions in emerging countries

Blockholdings in closely held corporations have been examined in the literature to understand the importance of the size and structure of minimal coalitions in a volatile macroeconomic environment. We show, theoretically and empirically, that three-member minimal controlling coalitions provide the best performance results because the portfolio of potential strategies of such coalitions can increase strategic choices in the boom-bust-recovery cycle, but coordination costs are not that high. We also show that “competition” between potential minimal controlling coalitions (of the same firm) with two or more members improves the firm’s performance. With respect to the characteristics of the institutional owners of one-member controlling coalitions, we found that firms controlled by foreigners and/or other non-financial firms and financial holdings performed better than the average firm. Our study indicates that the change of ownership structures in emerging countries is determined by the extant economic systems and through administrative interventions.     

A core equivalence theorem with an arbitrary communication structure

We formalize the concept of a communication structure by identifying it with a partition of the set of agents. Thus, a coalition can form if and only if it belongs to the given partition. Within this framework we are able to show that for every integer J≧2, if we put the uniform distribution on the space of partitions that contain exactly (or, no more than) J coalitions, the probability that such a partition will contain a blocking coalition for any Pareto optimal allocation which is bounded away from being competitive, is arbitrarily close to 1, as the number of individuals increases.     

Locally lipschitz cooperative games

A locally Lipschitz cooperative generalized game is described by its coalition worth function v defined on the set [0, 1]ⁿ of generalized (or fuzzy) coalitions of n players. We assume that v is positively homogeneous and locally Lipschitz. We propose the Clarke's generalized gradient ∂v(c^N) of v at the coalition c^N=(1,…,1) of all players as a set of solutions, and we study its property. We point out that it coincides with the core when v is super–additive and to the Shapley value when v is smooth.     

The proportion of blocking coalitions in atomless economies

In this paper we investigate the number of coalitions that block a given non-competitive allocation. In an atomless economy with a finite number of types we identify coalition with its profile. Considering profiles π that represent coalitions with the same proportions of types as in the whole society, we prove that there is a ball B_π with π as its center so that ‘almost half’ of the profiles in B_π are blocking. This result is an analogous result to that of Mas-Colell (1978) who dealt with large finite markets.     

Selection institutions and war aims

We explore how the sizes of the winning coalition and selectorate influence the war aims of states. Leaders who answer to a small winning coalition are more likely to seek territorial gain as a way to increase state resources. Nonterritorial war aims produce a commitment problem in that after the war the defeated state may not comply with the victor's demands. States with large winning coalitions are more willing to continue the war to remove the enemy leader as a solution to this commitment problem. We test our hypotheses against the Militarized Interstate Dispute data set, and we find some support for our argument. Received: June 2004, Accepted: April 2005, Correspondence to: James D. Morrow     

Cores of effectivity functions and implementation theory

In a committee where cooperative voting occurs, effectivity functions describe the blocking power of coalitions. It is a binary relation that says for each coalition T and each subset of outcomes B whether or not T can force the final outcome within B. The corresponding cooperative stability notion generalizes the familiar core of a simple game. We study those effectivity functions yielding a non-empty core for all preference profiles, of which additive effectivity functions are an example. This proves to be closely related to implementation by means of the strong equilibrium concept.     

Time horizons matter: the hazard rate of coalition governments and the size of government

This study examines how coalition governments affect the size of government, measured by total central government expenditure as a share of GDP. Existing studies suggest that the presence of multiple political parties within ruling coalitions generate common pool resource problems or bargaining inefficiencies which, in turn, leads to more government spending when coalition governments are in office. We demonstrate that coalition governments have shorter time horizons than single party governments and use that finding to motivate a simple formal model. The model shows that coalition governments have greater incentives to increase government spending because of a lower discount factor in office. Results from empirical models estimated on a global sample of 111 democracies between 1975 and 2007 provide strong statistical support for the aforementioned theoretical prediction. The empirical results remain robust when we control for alternative explanations, employ different estimation techniques, and use different measures of government spending.     

Walras degrees and probability of a blocking coalition at pareto allocations

We attempt to determine the probability of a blocking coalition from a notion of being non- Walrasian which does not rely on the explicit use of norms. The key concept introduced is that of Walras degrees. Theorem 1 gives the bounds of the probability of blocking in terms of these degrees. Theorem 2 gives the asymptotic conditional probability of a blocking coalition given that coalitions are losing. The relationship between the degrees of the conventional norms on allocations is also investigated.     

Spatial discounting and the gravity hypothesis

One of the central hypotheses in the study of spatial interaction behavior is the diminishing effect of distance on interaction. In this paper a parallel is drawn between two forms of this hypothesis: an external gravity interaction form which focuses directly on the empirically observable diminishing effect of distance on interaction, and an internal spatial discounting form which focuses rather on the diminishing effect of distance on spatial actors' preferences among interaction opportunities. The main result of the paper is to establish a connection between these two forms of the distance hypothesis. In particular, necessary and sufficient conditions on spatial actors' interaction preferences are established under which these two forms are equivalent, i.e., under which spatial discounting behavior is indistinguishable from gravity interaction behavior.     

The hybrid equilibria and core selection in exchange economies with externalities

This paper introduces a hybrid equilibrium concept that combines the elements of cooperative and non-cooperative behaviors in an exchange economy with externalities. For a fixed coalition structure (or a partition of traders), the hybrid equilibrium is a price and consumption bundle such that each coalition chooses a core solution from its budget set and the consumption bundles are feasible. It becomes the competitive equilibrium when the position is the finest, and it selects a core allocation when the partition is the coarsest. The paper provides sufficient conditions for the existence of a hybrid equilibrium for any coalition structure.     

Generalized coalitions and bargaining sets

We introduce new notions of bargaining set for mixed economies which rest on the idea of generalized coalitions (Aubin, 1979) to define objections and counter-objections. We show that the bargaining set defined through generalized coalitions coincides with competitive allocations under assumptions which are weak and natural in the mixed market literature. As a further result, we identify some additional properties that a generalized coalition must satisfy to object an allocation.     

From plurality rule to proportional representation

I consider the decision of a parliament that might change the electoral system from the plurality rule to proportional representation for forthcoming elections. Parties are office-motivated. They care about winning and about the share of seats obtained. I examine two different scenarios of how parties in government share the spoils of office: equally or proportionally to their share of seats. If the government is formed by a single party and parties expect that each party will obtain the same share of votes in the next election, the electoral rule will never be changed. Therefore, for a change to occur, the government should be formed by a coalition. I find that a change is more likely to occur when there is a larger number of parties and also when the spoils of office are shared equally among the members in the governing coalition. These results are extended to analyze the decision to change from a less proportional rule to a more proportional one.     

Multilateral negotiations and formation of coalitions

This paper analyses properties of games modeling multilateral negotiations leading to the formation of coalitions in an environment with widespread externalities. The payoff generated by each coalition is determined by an exogenous partition function (the parameter space). We show that in almost all games, except in a set of measure zero of the parameter space, the Markov perfect equilibrium value of coalitions and the state transition probability that describe the path of coalition formation is locally unique and stable. Therefore, comparative statics analysis are well-defined and can be performed using standard calculus tools. Global uniqueness does not hold in general, but the number of equilibria is finite and odd. In addition, a sufficient condition for global uniqueness is derived, and using this sufficient condition we show that there is a globally unique equilibrium in three-player superadditive games.     

On the formation of coalitions in infinite player games

This paper investigates the problem of determining when an infinite player game can be partitioned into countably many stable coalitions. An example is given of asuperadditive scalar measure game for which this is not possible and several positive results are presented. The final section of the paper takes up the problem of when a process of successive coalition formation can eventually lead to a division of all available resources. A theorem and a counterexample are presented for countable player games and the positive result is applied to the vector measure games considered earlier in the paper.     

Cooperative game with nondeterministic returns

We study a non-traditional cooperative game where returns from coalitions are nondeterministic. The long-standing concept of core can be generalized to reflect players’ contentment with their allocations. It is now imperative to formalize the restrictions, such as those pertaining to information, on allocations. The latter are also at times more conducive to fractional representations. With probabilistic structures added, nondeterministic returns become random variables, utility functions attain risk-attitude connotations, and the timing of players’ allocation resolutions gains significance. Under various conditions for utility functions, we show how various core concepts of the general game can be related to its traditionally defined auxiliaries. These developments help pave the way for our illustrations, within two distinct settings, that players’ increased risk aversion would promote the formation of the grand coalition.     

Coalition formation in general NTU games

A general nontransferable utility (NTU) game is interpreted as a collection of pure bargaining games that can be played by individual coalitions. The threatpoints or claims points respectively, in these pure bargaining games reflect the players' opportunities outside a given coalition. We develop a solution concept for general NTU games that is consistent in the sense that the players' outside opportunities are determined by the solution to a suitably defined reduced game. For any general NTU game the solution predicts which coalitions are formed and how the payoffs are distributed among the players.