An axiomatization of the Kalai-Smorodinsky solution when the feasible sets can be finite

We axiomatize the Kalai-Smorodinsky solution (1975) in the Nash bargaining problems if the feasible sets can be finite. We show that the Kalai-Smorodinsky solution is the unique solution satisfying Continuity (in the Hausdorff topology endowed with payoffs space), Independence (which is weaker than Nash's one and essentially equivalent to Roth (1977)'s one), Symmetry, Invariance (both of which are the same as in Kalai and Smorodinsky), and Monotonicity (which reduces to a little bit weaker version of the original if the feasible sets are convex). Received: 4 November 1999/Accepted: 6 June 2001     

Monotone-path Dutta-Ray solutions on convex games

It is well known that on the domain of convex games, the Dutta-Ray solution satisfies many desirable properties such as population-monotonicity, max consistency, converse max consistency, and conditional self-consistency. In this paper, we define a family of possibly non-symmetric and non-homogeneous generalizations of the Dutta-Ray solution, which we refer to as “monotone-path Dutta-Ray solutions.” We show that above four properties are preserved by our generalizations. Received: 25 August 2000/Accepted: 11 September 2001     

The replacement principle in economies with indivisible goods

 We consider the problem of allocating a list of indivisible goods and some amount of an infinitely divisible good among agents with equal rights on these resources, and investigate the implications of the following requirement on allocation rules: when the preferences of some of the agents change, all agents whose preferences are fixed should (weakly) gain, or they should all (weakly) lose. This condition is an application of a general principle of solidarity discussed in Thomson (1990b) under the name “replacement principle”. We look for selections from the no-envy solution satisfying this property. We show that in the general case, when the number of objects is arbitrary, there is no such selection. However, in the one-object case (a single prize), up to Pareto-indifference, there is only one selection from the no-envy solution satisfying the property. Such a solution always selects an envy-free allocation at which the winner of the prize is indifferent between his bundle and the losers’ common bundle. Received: 15 May 1995 / Accepted: 5 June 1996     

The consensus value: a new solution concept for cooperative games

To generalize the standard solution for 2-person TU games into n-person cases, this paper introduces a recursive two-sided negotiation process to establish cooperation between all players. This leads to a new solution concept for cooperative games: the consensus value. An explicit comparison with the Shapley value is provided, also at the axiomatic level. Moreover, a class of possible generalizations of the consensus value is introduced and axiomatized with the Shapley value at one end and the equal surplus solution at the other. Finally, we discuss a non-cooperative mechanism which implements the consensus value.     

Weakest collective rationality and the Nash bargaining solution

We propose a new axiom, weakest collective rationality (WCR) which is weaker than both weak Pareto optimality (WPO) in Nash’s (Econometrica 18:155–162, 1950) original characterization and strong individual rationality (SIR) in Roth’s (Math Oper Res 2:64–65, 1977) characterization of the Nash bargaining solution. We then characterize the Nash solution by symmetry (SYM), scale invariance (SI), independence of irrelevant alternatives (IIA) and our weakest collective rationality (WCR) axiom.     

Consistency, dummy and independence of irrelevant strategies for strategic games

The relationships between the consistency (CONS) principle and two other axioms, dummy (DUM) and independence of irrelevant strategies (IIS) for solution concepts on families of strategic form games are studied. If a solution satisfies DUM and IIS, then it also satisfies CONS (Peleg and Tijs 1996). The converse of this proposition is not true: CONS implies neither DUM nor IIS as shown in two simple examples, using the concept of coalition-proof Nash equilibrium. The axiom of weak dummy (WDUM) is introduced. WDUM, along with IIS, implies CONS. Moreover, CONS implies WDUM. Received: 13 August 1998/Accepted: 19 January 1999     

Axiomatizations of the normalized Banzhaf value and the Shapley value

A cooperative game with transferable utilities– or simply a TU-game – describes a situation in which players can obtain certain payoffs by cooperation. A solution concept for these games is a function which assigns to every such a game a distribution of payoffs over the players in the game. Famous solution concepts for TU-games are the Shapley value and the Banzhaf value. Both solution concepts have been axiomatized in various ways. An important difference between these two solution concepts is the fact that the Shapley value always distributes the payoff that can be obtained by the `grand coalition' consisting of all players cooperating together while the Banzhaf value does not satisfy this property, i.e., the Banzhaf value is not efficient. In this paper we consider the normalized Banzhaf value which distributes the payoff that can be obtained by the `grand coalition' proportional to the Banzhaf values of the players. This value does not satisfy certain axioms underlying the Banzhaf value. In this paper we introduce some new axioms that characterize the normalized Banzhaf value. We also provide an axiomatization of the Shapley value using similar axioms. Received: 10 April 1996 / Accepted: 2 June 1997     

Expected fair allocation in farsighted network formation

I consider situations in which a group of players extracts a value if they organise themselves in different network structures, and I define a solution concept to describe the decentralised decision that determines the network formation process and the allocation of the value. I demonstrate that there is a solution concept satisfying discounted expected versions of pairwise stability (Jackson and Wolinsky J Econ Theory 71:44–74, 1996) and fairness (Myerson Math Oper Res 2:225–229, 1977a) jointly with the requirement that the allocation rule be component efficient if the players’ discount factor is sufficiently low.     

Still more on the Tournament Equilibrium Set

Schwartz (Soc Choice Welfare 3:271–291, 1990) proposed a solution concept (the Tournament Equilibrium Set) for choosing from a tournament and stated some conjectures about this solution. Laffond et al. (Math Sci Hum 123:37–44, 1993) introduced further conjectures and showed the links between some of them. In this short note, we show that one of the conjectures stated by Schwartz (1990) is false. We also complete a result given in Laffond et al. (1993). I gratefully thank J.-F. Laslier for his remarks and for introducing me to this topic.     

On credible coalitional deviations by prudent players

In this paper we first explore the predictive power of the solution notion called conservative stable standard of behaviour (CSSB), introduced by Greenberg (The theory of social situations, 1990), in environments with farsighted players (as modelled in Xue, Econ Theory 11:603–627, 1998) as intuitively it is quite nice. Unfortunately, we find that CSSB has a number of undesirable properties: most importantly, it makes vacuous predictions for most natural social environments. Therefore, we introduce an intuitive refinement of this solution which we call conservative stable weak predictor. In settings of proper voting games, we explore some existence properties of this new solution and also show that it may not be unique. However, unfortunately, this refinement may also lead to non-intuitive vacuous predictions.     

Absorbing and generalized stable sets

Within the framework of an abstract system we establish the existing relationship between the following two solutions: The absorbing sets solution and the generalized stable sets solution.We are grateful to an anonymous referee for helpful comments. Financial support from the project 9/UPV-00035.321-13699/2001 is grateful acknowledged. Inarra gratefully acknowledges the hospitality of Brown University and the financial support from the Ministerio de Educación, Cultura y Deporte, PR 2003-0287.     

Resource-monotonic solutions to the problem of fair division when preferences are single-peaked

We consider the problem of fairly allocating an infinitely divisible commodity among a group of agents with single-peaked preferences. We search for solutions satisfying resource-monotonicity, the requirement that all agents be affected in the same direction when the amount to divide changes. Although there are resource-monotonic selections from the Pareto solution, there are none satisfying the distributional requirements of no-envy or individual rationality from equal division. We then consider the weakening of resource-monotonicity obtained by allowing only changes in the amount to divide that do not reverse the direction of the inequality between the amount to divide and the sum of the preferred amounts. We show that there is essentially a unique selection from the solution that associates with each economy its set of envy-free and efficient allocations satisfying this property of one-sided resource-monotonicity: it is the uniform rule, a solution that has played a central role in previous analyses of the problem.     

The ordinal egalitarian bargaining solution for finite choice sets

Rubinstein et al. (Econometrica 60:1171–1186, 1992) introduced the Ordinal Nash Bargaining Solution. They prove that Pareto optimality, ordinal invariance, ordinal symmetry, and IIA characterize this solution. A feature of their work is that attention is restricted to a domain of social choice problems with an infinite set of basic allocations. We introduce an alternative approach to solving finite social choice problems using a new notion called the Ordinal Egalitarian (OE) bargaining solution. This suggests the middle ranked allocation (or a lottery over the two middle ranked allocations) of the Pareto set as an outcome. We show that the OE solution is characterized by weak credible optimality, ordinal symmetry and independence of redundant alternatives. We conclude by arguing that what allows us to make progress on this problem is that with finite choice sets, the counting metric is a natural and fully ordinal way to measure gains and losses to agents seeking to solve bargaining problems.     

Graph monotonic values

A disturbing feature of most of the solution concepts for TU games with incomplete communication is that payments of players may decrease when they activate a new link. That can be considered as a drawback which does not occur for the Myerson value (Math Oper Res 2:225–229, 1977) of superadditive games. The present article offers a new axiomatic characterization of the Myerson value. We show that the Myerson value is the unique solution for games with communication structures verifying a set of properties including monotonicity with respect to the graph and coinciding with the Shapley value when the communication is complete.     

A universal meta bargaining implementation of the Nash solution

This paper follows van Damme (1986) in presenting a meta bargaining approach that justifies the Nash bargaining solution. But in contrast to van Damme's procedure our meta bargaining game is universal in the sense that all bargaining solutions are allowed as strategic choices in the meta bargaining game. Also our result holds true for any number n of players. Received: 31 July 2000/Accepted: 19 March 2001     

Single-peaked preferences with several commodities

We consider the problem of allocating m commodities among n agents with single-peaked preferences. When m≥2 and n=2 any strategy-proof and efficient solution is dictatorial. We propose an extension of the Uniform Rule that (in the two-agents case) is the only one that satisfies strategy-proofness, envy-freeness, and a weak requirement related to efficiency. Alternatively, the envy-freeness property may be replaced by weak-anonymity. Received: 7 November 1997/Accepted: 1 August 2000     

The application of building economics

This paper does not propose a solution to the problem, rather it identifies the scope of the problem. It is one which must be tackled urgently and methods must be devised for making information readily and easily handled. At this workshop, a brief presentation will be made of a possible solution which has been proposed for a public sector estate. It is hoped that the discussion will focus on: a method of establishing the size of the problem on an international scale; the key facts about an estate which management needs to know in order to manage the estate; and the means by which strategic management information should be collected, stored, updated and disseminated.     

An axiomatization of the Nash bargaining solution

I prove that ‘Disagreement Point Convexity’ and ‘Midpoint Domination’ characterize the Nash bargaining solution on the class of two-player bargaining problems and on the class of smooth bargaining problems. I propose an example to show that these two axioms do not characterize the Nash bargaining solution on the class of bargaining problems with more than two players. I prove that the other solutions that satisfy these two properties are not lower hemi-continuous. These different results refine the analysis of Chun (Econ Lett 34:311–316, 1990). I also highlight a rather unexpected link with the result of Dagan et al. (Soc Choice Welfare 19:811–823, 2002).     

Student views on campus sexual assault

Abstract

Objective: To report on college student opinions about the scope of college sexual misconduct (CSM), suggested university sanctions, and treatment of students found responsible of CSM.

Participants: In all, 23?US undergraduate students (14 females and 9 males) with a mean age of 20 years.

Methods: Students participated either in female, male, or mixed-sex focus groups that facilitated the discussion of factors related to CSM.

Results: Students provided in-depth feedback on the climate on US college campuses and factors related to CSM. They agreed upon CSM risk factors and context characteristics, but raised different male and female issues across sex groups. They further provided resolute suggestions for the solution of CSM, experienced treatment barriers, and limited victim reporting.

Conclusion: Student focus groups provide important information about the scope of CSM and offer valuable suggestions for the solution of the problem that may be crucial for the development of successful sexual assault interventions.     

Scoring rules: A cooperative game-theoretic approach

In this work we define the game of the alternatives for each preference profile, and establish relations between scoring rules and cooperative solution concepts for that game, such as the family of semivalues and the family of least square values. Received: 17 March 1997/Accepted: 12 May 1998