Stability and Nash implementation in matching markets with couples

We consider two-sided matching markets with couples. First, we extend a result by Klaus and Klijn (J Econ Theory 21: 75–106, 2005, Theorem 3.3) and show that for any weakly responsive couples market, there always exists a “double stable” matching, i.e., a matching that is stable for the couples market and for any associated singles market. Second, we show that for weakly responsive couples markets, the associated stable correspondence is (Maskin) monotonic and Nash implementable. In contrast, the correspondence that assigns all double stable matchings is neither monotonic nor Nash implementable.     

Matching with contracts: calculation of the complete set of stable allocations

Theory and Decision - For a many-to-many matching model with contracts, where all the agents have substitutable preferences, we provide an algorithm to compute the full set of stable allocations....     

Quasi stable outcomes in the assignment game

There is a great deal of literature on matching, theoretical, and empirical, concerning stable assignments and mechanisms that achieve them. The starting point of this study is an interesting question about assignment procedures: given a situation where some agents (the senior workers) on one side have a priority status, which changes the classical theory. The core of game may not be stable. We prove the existence of a quasi stable constrained core. This constrained core may not be a lattice but it is a finite and disjoint union of complete lattices that check the properties of the core’s classical assignment game. We study the manipulability questions that derive.     

On the existence of fair matching algorithms

We analyze the Gale-Shapley matching problem within the context of Rawlsian justice. Defining a fair matching algorithm by a set of 4 axioms (Gender Indifference, Peer Indifference, Maximin Optimality, and Stability), we show that not all preference profiles admit a fair matching algorithm, the reason being that even this set of minimal axioms is too strong in a sense. Because of conflict between Stability and Maximin Optimality, even the algorithm which generates the mutual agreement match, paradoxically, has no chance to be fair.We then relax the definition of fairness (by giving preference to Stability over Maximin Optimality) and again find that some preference profiles admit a fair matching algorithm, while others still do not, but the mutual agreement algorithm now is fair under this definition.The paper then develops a test, which determines, for a given preference profile, whether a fair algorithm exists or not.     

Living without state-independence of utilities

This article is concerned with the representation of preferences which do not satisfy the ordinary axioms for state-independent utilities. After suggesting reasons for not being satisfied with solutions involving state-dependent utilities, an alternative representation shall be proposed involving state-independent utilities and a situation-dependent factor. The latter captures the interdependencies between states and consequences. Two sets of axioms are proposed, each permitting the derivation of subjective probabilities, state-independent utilities, and a situation-dependent factor, and each operating in a different framework. The first framework involves the concept of a decision situation—consisting of a set of states, a set of consequences and a preference relation on acts; the probabilities, utilities and situation-dependent factor are elicited by referring to other, appropriate decision situations. The second framework, which is technically related, operates in a fixed decision situation; particular “subsituations” are employed in the derivation of the representation. Possible interpretations of the situation-dependent factor and the notion of situation are discussed.     

Finite Alternating-Move Arbitration Schemes and the Equal Area Solution

We start by considering the Alternate Strike (AS) scheme, a real-life arbitration scheme where two parties select an arbitrator by alternately crossing off at each round one name from a given panel of arbitrators. We find out that the AS scheme is not invariant to “bad” alternatives. We then consider another alternating-move scheme, the Voting by Alternating Offers and Vetoes (VAOV) scheme, which is invariant to bad alternatives. We fully characterize the subgame perfect equilibrium outcome sets of these above two schemes in terms of the rankings of the parties over the alternatives only. We also identify some of the typical equilibria of these above two schemes. We then analyze two additional alternating-move schemes in which players’ current proposals have to either honor or enhance their previous proposals. We show that the first scheme’s equilibrium outcome set coincides with that of the AS scheme, and the equilibrium outcome set of the second scheme coincides with that of the VAOV scheme. Finally, it turns out that all schemes’ equilibrium outcome sets converge to the Equal Area solution’s outcome of cooperative bargaining problem, if the alternatives are distributed uniformly over the comprehensive utility possibility set and as the number of alternatives tends to infinity. Journal of Economic Literature Classification Number: C72.     

The Value of a Probability Forecast from Portfolio Theory

A probability forecast scored ex post using a probability scoring rule (e.g. Brier) is analogous to a risky financial security. With only superficial adaptation, the same economic logic by which securities are valued ex ante – in particular, portfolio theory and the capital asset pricing model (CAPM) – applies to the valuation of probability forecasts. Each available forecast of a given event is valued relative to each other and to the “market” (all available forecasts). A forecast is seen to be more valuable the higher its expected score and the lower the covariance of its score with the market aggregate score. Forecasts that score highly in trials when others do poorly are appreciated more than those with equal success in “easy” trials where most forecasts score well. The CAPM defines economically rational (equilibrium) forecast prices at which forecasters can trade shares in each other’s ex post score – or associated monetary payoff – thereby balancing forecast risk against return and ultimately forming optimally hedged portfolios. Hedging this way offers risk averse forecasters an “honest” alternative to the ruse of reporting conservative probability assessments.     

Coalitional stability and efficiency of partitions in matching problems

?zkal-Sanver (Theory Decis 59:193–205, 2005) studies stability and efficiency of partitions of agents in two-sided matching markets in which agents can form partitions by individual moves only, and a matching rule determines the matching in each coalition in a partition. In this study, we present the relationship between stability and efficiency of partitions that is analyzed for several matching rules and under various membership property rights codes, now allowing coalitional moves.     

结构分销网络与市场定位的刚性匹配

市场定位决定了营销的基本策略,因此,也是结构分销网络在设计时必须考虑的刚性匹配。市场定位既决定了分销网络的终端形式及逆向设计原则,决定了分销网络终端的密度,也决定了分销网络终端渠道的管理层次与幅度及区域市场的选择方式。     

Stability and Efficiency of Partitions in Matching Problems

We define two versions of stability and efficiency of partitions and analyze their relationships for some matching rules. The stability and efficiency of a partition depends on the matching rule φ. The results are stated under various membership property rights axioms. It is shown that in a world where agents can freely exit from and enter coalitions, whenever the matching rule is individually rational and Pareto optimal, the set of φ-stable and φ-efficient partitions coincide and it is unique: the grand coalition. Then we define a weaker version of stability and efficiency, namely specific to a given preference profile and find some negative results for stable matching rules.     

Quasi-Bayesian Analysis Using Imprecise Probability Assessments And The Generalized Bayes’ Rule

The generalized Bayes’ rule (GBR) can be used to conduct ‘quasi-Bayesian’ analyses when prior beliefs are represented by imprecise probability models. We describe a procedure for deriving coherent imprecise probability models when the event space consists of a finite set of mutually exclusive and exhaustive events. The procedure is based on Walley’s theory of upper and lower prevision and employs simple linear programming models. We then describe how these models can be updated using Cozman’s linear programming formulation of the GBR. Examples are provided to demonstrate how the GBR can be applied in practice. These examples also illustrate the effects of prior imprecision and prior-data conflict on the precision of the posterior probability distribution.     

`Sex-Equal' Stable Matchings

The paper defines a measure on the set of stable matchings in the marriage problem. This measure is based on the minimization of the envy difference between the sets of men and women, while preserving stability and selects stable matchings with the least conflict of interest between both groups of agents. The solution concept proposed is called Sex-equal Matching (SEM) and the paper also provides an algorithm to compute the set of SEM.     

On Myopic Stability Concepts for Hedonic Games

We present a unified look at myopic stability concepts for hedonic games, and discuss the status of the existence problems of stable coalition structures. In particular, we show that contractual strictly core stable coalition structures always exist, and present a sufficient condition for the existence of contractually Nash stable coalition structures on the class of separable games. We gratefully acknowledge financial support from the Alexander von Humboldt Foundation (D. Dimitrov)“by “D. Dimitrov gratefully acknowledges financial support from the Alexander von Humboldt Foundation.     

Finding socially best spanning trees

This article combines Social Choice Theory with Discrete Optimization. We assume that individuals have preferences over edges of a graph that need to be aggregated. The goal is to find a socially “best” spanning tree in the graph. As ranking all spanning trees is becoming infeasible even for small numbers of vertices and/or edges of a graph, our interest lies in finding algorithms that determine a socially “best” spanning tree in a simple manner. This problem is closely related to the minimum (or maximum) spanning tree problem in Discrete Optimization. Our main result shows that for the various underlying ranking rules on the set of spanning trees discussed in this article, the sets of “best” spanning trees coincide. Moreover, a greedy algorithm based on a transitive group ranking on the set of edges will always provide such a “best” spanning tree.     

Evaluating Children's Services: Recent Conceptual and Methodological Developments

This article considers recent innovations and challenges withrespect to the evaluation of children’s services interventions.It sets out a method for designing and evaluating services thatis based on research evidence gathered on individual cases andthat permits revision of those services in the light of emergingresults. It starts by describing briefly different ways of identifyinga discrete group of children with similar needs. It then outlinesapproaches to ensuring that an intervention for those childrenis underpinned by theory and research evidence–includingthe idea of ‘logic modelling’–before discussingthe importance of capturing accurately how well the interventionis implemented. Experimental and non-experimental methods ofassessing an intervention’s effectiveness are considered,with particular emphasis on techniques for enhancing the causalinference that can be drawn from studies and the importanceof matching method and purpose. The article also demonstrateshow the principles and methods used in relation to evaluatingservices for groups can be applied in clinical work with individualcases, and identifies the benefits of this general approachto evaluation over and above the information that it provideson what works.     

FAIR DIVISION OF INDIVISIBLE ITEMS

This paper analyzes criteria of fair division of a set of indivisible items among people whose revealed preferences are limited to rankings of the items and for whom no side payments are allowed. The criteria include refinements of Pareto optimality and envy-freeness as well as dominance-freeness, evenness of shares, and two criteria based on equally-spaced surrogate utilities, referred to as maxsum and equimax. Maxsum maximizes a measure of aggregate utility or welfare, whereas equimax lexicographically maximizes persons' utilities from smallest to largest. The paper analyzes conflicts among the criteria along with possibilities and pitfalls of achieving fair division in a variety of circumstances.     

Conservative Stable Standards of Behavior and φ-Stable Sets

Within Luo’s (2001, J. Math. Econ. 36, 95–109) framework of a general system, I establish an equivalence theorem for the conservative stable standard of behavior (CSSB for short) developed by J. Greenberg (“The Theory of Social Situation: An Alternative Game-Theoretic Approach,” Cambridge University Press, 1990). It is shown that a standard of behavior for a situation is a CSSB if, and only if, its graph is a φ-stable set for the associated general system.     

A model of influence with an ordered set of possible actions

In the article, a yes–no model of influence is generalized to a multi-choice framework. We introduce and study the weighted influence indices of a coalition on a player in a social network where the players have an ordered set of possible actions. Each player has an inclination to choose one of the actions. Due to the mutual influence among players, the final decision of each player may be different from his original inclination. In a particular case, the decision of the player is closer to the inclination of the influencing coalition than his inclination was, i.e., the distance between the inclinations of the player and of the coalition is greater than the distance between the decision of the player and the inclination of the coalition in question. The weighted influence index which captures such a case is called the weighted positive influence index. We also consider the weighted negative influence index where the final decision of the player goes farther away from the inclination of the coalition. We consider several influence functions defined in the generalized model of influence and study their properties. The concept of a follower of a given coalition and its particular case, a perfect follower, are defined. The properties of the set of followers are analyzed.     

Characterizations of the β- and the Degree Network Power Measure

A symmetric network consists of a set of positions and a set of bilateral links between these positions. For every symmetric network we define a cooperative transferable utility game that measures the “power” of each coalition of positions in the network. Applying the Shapley value to this game yields a network power measure, the β-measure, which reflects the power of the individual positions in the network. Applying this power distribution method iteratively yields a limit distribution, which turns out to be proportional to the well-known degree measure. We compare the β-measure and degree measure by providing characterizations, which differ only in the normalization that is used.      

中国农村宗教复兴与“宗教”的中国命运

中国农村宗教复兴是改革开放以来最“出人意料”的现象之一。对此,学界提出了“传统的发明”、“国家-社会关系”、“宗教市场”三种解释模式。本文认为,解释中国农村宗教复兴,不能将宗教现象还原为“政治”或“经济”等其他范畴,而应将之视为一种自成一类的事实,一种人的基本条件,同时应充分理解政治精英和知识精英在中国近现代史上对 “宗教”的塑造过程。中国农村的宗教复兴在很大程度上游离于这一塑造过程之外,因此,可能存在着尚不为学界所充分认识的社会机制,有着提供本土理论的潜力。本文认为,在世俗化理论和市场理论之外,应该尝试使用“礼物模式”探索这一社会机制。