Existence of the core in a heterogeneous divisible commodity exchange economy

We consider the exchange of a heterogeneous divisible commodity modeled as a measurable space. Under rational, continuous and convex preferences over characteristic measures a weak core is shown to exist. Further, a core exists if characteristic measures are mutually absolutely continuous. Applied to the land trading economy, the core existence results in Berliant (J Math Econ 14:53–56, 1985) and Dunz (Reg Sci Urban Econ 21:73–88, 1991) are obtained.     

一个NTU博弈的模糊延拓方法

对NTU合作博弈给出了一种模糊延拓方法,得到了模糊延拓后的模糊核心,并举例进行了说明。     

Towards an axiomatization of the core-center

The core-center is an allocation rule introduced in González-Díaz and Sánchez-Rodríguez (González-Díaz, J., Sánchez-Rodríguez, E., 2007. A natural selection from the core of a TU game: The core-center. International Journal of Game Theory 36, 27–46. doi: 10.1007/s00182-007-0074-5) for the class of games with a non-empty core. In this paper we present a weighted additivity axiom, which we call trade-off property, and use it to obtain two characterizations of the core-center.     

On the core and nucleolus of minimum cost spanning tree games

We develop two efficient procedures for generating cost allocation vectors in the core of a minimum cost spanning tree (m.c.s.t.) game. The first procedure requires O(n ²) elementary operations to obtain each additional point in the core, wheren is the number of users. The efficiency of the second procedure, which is a natural strengthening of the first procedure, stems from the special structure of minimum excess coalitions in the core of an m.c.s.t. game. This special structure is later used (i) to ease the computational difficulty in computing the nucleolus of an m.c.s.t. game, and (ii) to provide a geometric characterization for the nucleolus of an m.c.s.t. game. This geometric characterization implies that in an m.c.s.t. game the nucleolus is the unique point in the intersection of the core and the kernel. We further develop an efficient procedure for generating fair cost allocations which, in some instances, coincide with the nucleolus. Finally, we show that by employing Sterns' transfer scheme we can generate a sequence of cost vectors which converges to the nucleolus. Part of this research was done while the author was visiting the Department of Operations Research at Stanford University. This research was partially supported by Natural Sciences and Engineering Research Council Canada Grant A-4181.     

An axiomatization of the nucleolus

In this paper we give a set of axioms characterizing the nucleolus of a TU-game on the class of zero-monotonic games as well as on the class of balanced games. Among the axioms there are familiar ones like anonymity (ANN) and covariance (COV), a restriction of a known property, the restricted reduced game property (ResRGP) and a continuity axiom (LIM). Further we introduce another property of the nucleolus — the alternative reduced game property (AltRGP) — and show that this property together with the ones mentioned before characterizes the nucleolus almost completely on its definition set.     

An axiomatization of events

Most approaches to information modelling are so-called snapshot approaches. This means that they focus on static properties of a universe of discourse only. Some approaches consider the temporal dimension of a universe of discourse. In these approaches the concept of event is central. It is used to denote, e.g., a decision or an action which takes place at a certain time point.In this paper the concept of event is analyzed within the framework of first-order predicate logic. An axiom system for discrete time points and axiom schemes for events is presented. It is shown that the axiom schemes obtained apply to a number of cases with wide applicability. Further, several remaining problems are pointed out.This work is supported by the National Swedish Board for Technical Development (STU).     

An axiomatization of the egalitarian solutions

The egalitarian solutions for general cooperative games which were defined and axiomatized by Kalai and Samet, are compared to the Harsanyi solution. It is shown that axioms used by Hart to characterize the Harsanyi solution can be used to characterize the (symmetric) egalitarian solution. The only changes needed are the omission of the scale covariance axiom and the inclusion, in the domain of the solution, of games which lack a certain smoothness requirement.     

An axiomatization of the Banzhaf value

An axiomatization of the Banzhaf value is given. It is based on a version of three axioms, which are common to all the semi-values, and on an additional reduction axiom.     

Axiomatizations of the core on the universal domain and other natural domains

We prove that the core on the set of all transferable utility games with players contained in a universe of at least five members can be axiomatized by the zero inessential game property, covariance under strategic equivalence, anonymity, boundedness, the weak reduced game property, the converse reduced game property, and the reconfirmation property. These properties also characterize the core on certain subsets of games, e.g., on the set of totally balanced games, on the set of balanced games, and on the set of superadditive games. Suitable extensions of these properties yield an axiomatization of the core on sets of nontransferable utility games. Received September 1999/Final version December 2000     

An axiomatization of the weighted NTU value

Non-symmetric generalizations of the non-transferable utility (NTU) are defined and characterized axiomatically. The first of these is a weighted NTU value that is identical to the (symmetric) NTU value when players have the same weights. On the class of transferable utility games, this weighted NTU value coincides with the weighted Shapley value and on the pure bargaining games it coincides with the non-symmetric Nash bargaining solution. A further extension, the random order NTU value, is also defined and axiomatized and its relationship to the core is discussed.     

Complexity of core allocation for the bin packing game

This paper provides complexity results and develops optimal algorithms for core membership and emptiness tests of the bin packing game. Our algorithms find the maximum surplus profit, the least integer core value, and the minimum value required by the grand coalition for the existence of an integer core allocation.     

An axiomatization of the consistent non-transferable utility value

The Maschler–Owen consistent value for non-transferable utility games is axiomatized, by means of a marginality axiom.Previous versions: October 2003 (Center for the Study of Rationality DP-337), December 2004. Research partially supported by a grant of the Israel Academy of Sciences and Humanities. The author thanks Andreu Mas-Colell, Bezalel Peleg, Peter Sudhölter, the referees, and the editor for their comments and suggestions.     

An axiomatization of minimal curb sets

Norde et al. [Games Econ. Behav. 12 (1996) 219] proved that none of the equilibrium concepts in the literature on equilibrium selection in finite strategic games satisfying existence is consistent. A transition to set-valued solution concepts overcomes the inconsistency problem: there is a multiplicity of consistent set-valued solution concepts that satisfy nonemptiness and recommend utility maximization in one-player games. The minimal curb sets of Basu and Weibull [Econ. Letters 36 (1991) 141] constitute one such solution concept; this solution concept is axiomatized in this article.     

An axiomatization of the modified Banzhaf Coleman index

In this paper we provide a characterization for the modified Banzhaf-Coleman indexes by employing some amalgamation axioms as Lehrer (1988) did for the Banzhaf-Coleman indexes. Final version: June 2001     

多选择NTU对策核心的一个非空条件及公理化

提出了\pi-均衡多选择NTU对策的概念,证明了\pi-均衡多选择NTU对策的核心非空, 定义了多选择NTU对策的非水平性质和缩减对策,给出了相容性和逆相容性等概念. 用个体合理性、单人合理性、相容性和逆相容性对非水平多选择NTU对策的核心进行了公理化.