The non-emptiness of the core of a partition function form game

The purpose of this paper is to provide a necessary and sufficient condition for the non-emptiness of the core for partition function form games. We generalize the Bondareva–Shapley condition to partition function form games and present the condition for the non-emptiness of “the pessimistic core”, and “the optimistic core”. The pessimistic (optimistic) core describes the stability in assuming that players in a deviating coalition anticipate the worst (best) reaction from the other players. In addition, we define two other notions of the core based on exogenous partitions. The balanced collections in partition function form games and some economic applications are also provided.     

The general nucleolus and the reduced game property

The nucleolus of a TU game is a solution concept whose main attraction is that it always resides in any nonempty -core. In this paper we generalize the nucleolus to an arbitrary pair (,F), where is a topological space andF is a finite set of real continuous functions whose domain is . For such pairs we also introduce the least core concept. We then characterize the nucleolus forclasses of such pairs by means of a set of axioms, one of which requires that it resides in the least core. It turns out that different classes require different axiomatic characterizations.One of the classes consists of TU-games in which several coalitions may be nonpermissible and, moreover, the space of imputations is required to be a certain generalized core. We call these gamestruncated games. For the class of truncated games, one of the axioms is a new kind ofreduced game property, in which consistency is achieved even if some coalitions leave the game, being promised the nucleolus payoffs. Finally, we extend Kohlberg's characterization of the nucleolus to the class of truncated games.     

The egalitarian solution and reduced game properties in convex games

The main purpose of this paper is to axiomatise the egalitarian solution of Dutta and Ray over the class of convex games. The main axioms used are the two reduced game properties due to Davis-Maschler and Hart-Mas Colell. The egalitarian solution is the only solution satisfying either of the two reduced game properties and agreeing with the egalitarian solution on two person games. Moreover, it is also shown that there is no solution satisfying symmetry, individual rationality and a monotonicity condition on two-person games and which simultaneously satisfies both the reduced game properties.     

The kernel,the bargaining set and the reduced game

We present an example showing that forxK(N, v, B) the section ofK(N, v, B) atx| _{N-B k} may be a proper subset ofK(B _k, v_x, X_k). Further we prove that under appropriate conditions these two sets coincide. For the bargaining set we prove a similar result.We are grateful to an anonymous referee for valuable comments.     

An NTU value under complement reduced game

The paper follows Kalai and Samet’s (Econometrica 53:307–327, 1985) construction to define a possible extension of the equal allocation of nonseparable costs (EANSC) to games without transferable utilities. We offer a characterization of the EANSC based on the axiom of independence of irrelevant monotonic transformation [Chang and Hwang (Int J Game Theory 32:253–271, 2003) introduced this axiom, and they named it independence of irrelevant expansions. The referee points out that the terminology is inappropriate. So, we change the name.] introduced by Chang and Hwang (Int J Game Theory 32:253–271, 2003) as well as on several familiar axioms. Specifically, we show that the EANSC is the only solution to satisfy Pareto optimality, translation covariance, anonymity, TU-bilateral consistency (or TU-converse consistency), aggregate monotonicity, and independence of irrelevant monotonic transformation.     

On the reduced game property and its converse

We investigate the relationship between two solutions, the core and the prekernel, and reduced games of coalitional games. An axiomatic characterization of these two solutions is obtained by means of the reduced game property and its converse.     

The prenucleolus and the reduced game property: Equal treatment replaces anonymity

In his paper, Sobolev [1975] characterized the prenucleolus as the unique solution concept, defined over the class of cooperative games that satisfies single valuedness, anonymity, covariance under strategic equivalence and reduced game property (consistency).In this paper we show that anonymity can be weakened and replaced by a requirement of equal treatment (symmetry).     

A reduced form model for ESO valuation

In this paper we extend a reduced form model for the valuation of employee share options (ESOs) to incorporate employee departure, and company takeover. We also allow for performance linked vesting and other exotic features specific to ESOs. We clarify the assumptions underlying the reduced form model, and discuss their implications. We analyze the probabilistic structure of the model which includes an explicit characterization of the set of equivalent martingale measures, as well as the computation of the variance optimal martingale measure and the minimal martingale measure. Moreover, we deduce an additive decomposition of the relative entropy. Particular ESO specifications are studied emphasizing different aspects of the proposed framework. In this context, we also provide strict no-arbitrage bounds for ESO prices by applying optimal stopping. Furthermore, possible limitations of the proposed model are explored by examining departures from the crucial assumptions of no-arbitrage, i.e. by considering the effects of the employee having inside information.     

The sigma-core of a cooperative game

This paper is concerned with the existence of (σ-additive) measures in the core of a cooperative game. The main theorem shows, for a capacityu on the Borel sets of a metric space, that to each additive set function, majorized byu and agreeing withu on a system of closed sets, there exists a measure having these same properties. This theorem is applied, in combination with known core theorems, to the case of a cooperative game defined on the Borel sets of a metric space and whose conjugate is a capacity.     

一种资源投入不确定情形下的合作博弈形式及收益分配策略

首先,将经典合作博弈进行扩展,提出了一类模糊联盟合作博弈的通用形式,涵盖常见三种模糊联盟合作博弈,即多线性扩展博弈、比例模糊博弈与Choquet积分模糊博弈.比例模糊博弈、Choquet积分模糊博弈的Shapley值均可以作为一种特定形式下模糊联盟合作博弈的收益分配策略,但是对于多线性扩展博弈的Shapley值一直关注较少,因此利用经典Shapley值构造出多线性扩展博弈的Shapley值,以此作为一种收益分配策略.最后,通过实例分析了常见三类模糊联盟合作博弈的形式及其对应的分配策略,分析收益最大的模糊联盟合作对策形式及最优分配策略,为不确定情形下的合作问题提供了一定的收益分配依据.     

Pricing catastrophe options with counterparty credit risk in a reduced form model

In this paper, we study the price of catastrophe options with counterparty credit risk in a reduced form model. We assume that the loss process is generated by a doubly stochastic Poisson process, the share price process is modeled through a jump-diffusion process which is correlated to the loss process, the interest rate process and the default intensity process are modeled through the Vasicek model. We derive the closed form formulae for pricing catastrophe options in a reduced form model. Furthermore, we make some numerical analysis on the explicit formulae.     

Uniqueness of form factors for the reduced sine-Gordon model

Using certain asymptotic conditions, we prove the uniqueness of the form factors of the energy-momentum tensor for the reduced sine-Gordon model (2/3) (RSG(2/3)). Bibliography: 5 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 199, 1992, pp. 177–181. Translated by I. A. Izergina.     

The equilibria of a multiple objective game

For a multiple objective game, we introduce its cooperative, non-cooperative, hybrid and quasi-hybrid solution concepts and prove their existence. JEL #: C70, C71, C72The author is indebted to Truman Bewley, Pradeep Dubey, Zhimin Huang, Tatsuro Ichiishi, David Pearce, Herbert E. Scarf, Lloyd Shapley, Martin Shubik, Lin Zhou and the Editor and an anonymous referee ofThe International Journal of Game Theory for their valuable dicussions and suggestions. The support of the 1990–91 Anderson Prize Fellowship from the Cowles Foundation for Research in Economics at Yale University is also appreciated.     

The dynamics of a triopoly Cournot game

This paper reconsiders the Cournot oligopoly (noncooperative) game with iso-elastic demand and constant marginal costs, one of the rare cases where the reaction functions can be derived in closed form. It focuses the case of three competitors, and so also extends the critical line method for non-invertible maps to the study of critical surfaces in 3D. By this method the various bifurcations of the attractors and their basins are studied. As a special case the restriction of the map to an invariant plane when two of the three firms are identical is focused.     

The positive core of a cooperative game

The positive core is a nonempty extension of the core of transferable utility games. If the core is nonempty, then it coincides with the core. It shares many properties with the core. Six well-known axioms that are employed in some axiomatizations of the core, the prenucleolus, or the positive prekernel, and one new intuitive axiom, characterize the positive core for any infinite universe of players. This new axiom requires that the solution of a game, whenever it is nonempty, contains an element that is invariant under any symmetry of the game.     

The vertex picking game and a variation of the game of dots and boxes

A two-player game played on a graph is introduced and completely solved. As a consequence, a solution to a simplified variation of a well-known game called dots and boxes played on a grid [2] is given.     

On the reduced game property for and the axiomatization of theT-value of TU-games

Summary The τ-value is a one-point solution concept for transferable utility (TU-) games. The paper introduces a particular type of a reduced game. It is established that the τ-value possesses the reduced game property with respect to the reduced game presented. That is, there is no inconsistency in what the players of the reduced game receive-either in the original game or in the reduced game-according to the τ-value concept. In addition, the paper provides an axiomatic characterization of the τ-value in terms of the relevant reduced game property and standardness for two-person games.     

The core of a further m-sided assignment game

A further generalization of the Shapley-Shubik housing market is considered in which there are m types of individuals instead of two. This is different from the generalization of Quint. These games can have empty cores.