The least square prenucleolus and the least square nucleolus. Two values for TU games based on the excess vector

The nucleolus and the prenucleolus are solution concepts for TU games based on the excess vector that can be associated to any payoff vector. Here we explore some solution concepts resulting from a payoff vector selection based also on the excess vector but by means of an assessment of their relative fairness different from that given by the lexicographical order. We take the departure consisting of choosing the payoff vector which minimizes the variance of the resulting excesses of the coalitions. This procedure yields two interesting solution concepts, both a prenucleolus-like and a nucleolus-like notion, depending on which set is chosen to set up the minimizing problem: the set of efficient payoff vectors or the set of inputations. These solution concepts, which, paralleling the prenucleolus and the nucleolus, we call least square prenucleolus and least square nucleolus, are easy to calculate and exhibit nice properties. Different axiomatic characterizations of the former are established, some of them by means of consistency for a reasonable reduced game concept.     

Random reduction consistency of the Weber set,the core and the anti-core

In this paper we introduce a new consistency condition and provide characterizations for several solution concepts in TU cooperative game theory. Our new consistency condition, which we call the random reduction consistency, requires the consistency of payoff vectors assigned by a solution concept when one of the players is removed with some probability. We show that the random reduction consistency and other standard properties characterize the Weber set, the convex hull of the marginal contribution vectors. Another salient feature of random reduction consistency is that, by slightly changing its definition, we can characterize the core and the anti-core in a parallel manner. Our result enables us to compare the difference between the three solution concepts from the viewpoint of consistency.     

Core extensions for non-balanced TU-games

A family of core extensions for cooperative TU-games is introduced. These solution concepts are non-empty when applied to non-balanced games yet coincide with the core whenever the core is non-empty. The extensions suggest how an exogenous regulator can sustain a stable and efficient outcome, financing a subsidy via individual taxes. Economic and geometric properties of the solution concepts are studied. When taxes are proportional, the proportional prenucleolus is proposed as a single-valued selection device. An application of these concepts to the decentralization of a public goods economy is discussed. We wish to thank the editor, a referee, an anonymous reviewer, Beth Allen, Marc Dudey, Yakar Kannai, Herve Moulin, Marcel Richter, Luis Sánchez-Mier, and the participants in the Microeconomic Theory Workshop at Rice University for their helpful comments.     

Moral concepts: From thickness to response-dependence

The paper examines three tenets of Dancy's meta-ethics, finds them incompatible, and proposes a response-dependentist (or response-dispositional) solution. The first tenet is the central importance of thick concepts and properties. The second is that such concepts essentially involve response(s) of observers, which Dancy interprets in a way that fits the pattern of context-dependent resultance: thick concepts are well suited for the particularist grounding of moral theory. However, and this is the third tenet, in his earlier paper (1986) Dancy forcefully argues against response-dispositional accounts of moral concepts and properties. The present paper argues that an anti-dispositional view is incompatible with the first two points concerning thick concepts. If thick concepts and properties are paramount and ubiquitous in moral thought and reality, and if they are essentially tied to human responses, then anti-dispositionalism is false. Dancy himself avoids obvious contradiction by characterizing thick items (concepts) differently from the usual characterization of response-dependent items. Actions that satisfy thick concepts do so in virtue of meriting a determinate response. The (non-reductionist) response-dependentist usually puts it slightly differently: such actions satisfy a given moral concepts in virtue of eliciting a merited response. I have argued at length that this tenuous difference in formulation is too weak to support a relevant difference in rebus. If the argument is right, Dancy is implicitly committed to a kind of response-dependentism. Finally, the particularist should embrace thick concepts and properties, and reject anti-dispositionalism. However, this would bring back the analogy with color and other secondary qualities. Since there are ceteris paribus laws governing such properties, the analogy suggests that moral properties might also be best accounted for by a ceteris paribus, or hedged account, a compromise between traditional generalism and the particularism of Dancy's variety.     

多目标规划的r—有效解和r—最优

本文引入有限维向量空间的r-序类概念,讨论了它们的基本性质。在此基础上,定义了多目标规划的r-有效解和r-最优解,研究了它们与其它有关解之间的关系。     

多目标规划的局部较多最优性和局部较多有效性

多目标规划的局部较多最优性和局部较多有效性胡毓达（上海交通大学应用数学系，２０００３０）国家自然科学基金资助项目．１９９１年８月２７日收到．一、引言考虑多目标规划问题其中ＸＳ是约束集（开集（ｍ２）是向量目标函数．对于问题（ＶＭＰ），自５０年代以来人们...     

Symmetry and <Emphasis Type="Italic">p</Emphasis>-Stability

A symmetry of a game is a permutation of the player set and their strategy sets that leaves the payoff functions invariant. In this paper we introduce and discuss two relatively mild symmetry properties for set-valued solution concepts (that are equivalent when the solution concepts are single-valued) and show using examples that stable sets satisfy neither version. These examples also show that for every integer q, there exists a game with an equilibrium component of index q.Received February 2002/Revised November 2003Supported by an EPSRC doctoral grant.     

The Karush-Kuhn-Tucker optimality conditions for multi-objective programming problems with fuzzy-valued objective functions

The KKT optimality conditions for multiobjective programming problems with fuzzy-valued objective functions are derived in this paper. The solution concepts are proposed by defining an ordering relation on the class of all fuzzy numbers. Owing to this ordering relation being a partial ordering, the solution concepts proposed in this paper will follow from the similar solution concept, called Pareto optimal solution, in the conventional multiobjective programming problems. In order to consider the differentiation of fuzzy-valued function, we invoke the Hausdorff metric to define the distance between two fuzzy numbers and the Hukuhara difference to define the difference of two fuzzy numbers. Under these settings, the KKT optimality conditions are elicited naturally by introducing the Lagrange function multipliers.     

Price Expectations and Cobwebs Under Uncertainty

Classical approaches to location problems are based on the minimization of the average distance (the median concept) or the minimization of the maximum distance (the center concept) to the service facilities. The median solution concept is primarily concerned with the spatial efficiency while the center concept is focused on the spatial equity. The k-centrum model unifies both the concepts by minimization of the sum of the k largest distances. In this paper we investigate a solution concept of the conditional median which is a generalization of the k-centrum concept taking into account the portion of demand related to the largest distances. Namely, for a specified portion (quantile) of demand we take into account the entire group of the corresponding largest distances and we minimize their average. It is shown that such an objective, similar to the standard minimax, may be modeled with a number of simple linear inequalities. Equitable properties of the solution concept are examined.     

Solution concepts in vector optimization: a fresh look at an old story

Over the past decades various solution concepts for vector optimization problems have been established and used: among them are efficient, weakly efficient and properly efficient solutions. In contrast to the classical approach, we define a solution to be a set of efficient solutions on which the infimum of the objective function with respect to an appropriate complete lattice (the space of self-infimal sets) is attained. The set of weakly efficient solutions is not considered to be a solution, but weak efficiency is essential in the construction of the complete lattice. In this way, two classic concepts are involved in a common approach. Several different notions of semicontinuity are compared. Using the space of self-infimal sets, we can show that various originally different concepts coincide. A Weierstrass existence result is proved for our solution concept. A slight relaxation of the solution concept yields a relationship to properly efficient solutions.     

Some results on cooperative interval games

Uncertainty is a daily presence in the real world. It affects our decision-making and may have influence on cooperation. On many occasions, uncertainty is so severe that we can only predict some upper and lower bounds for the outcome of our actions, i.e. payoffs lie in some intervals. A suitable game theoretic model to support decision-making in collaborative situations with interval data is that of cooperative interval games. Solution concepts that associate with each cooperative interval game sets of interval allocations with appealing properties provide a natural way to capture the uncertainty of coalition values into the players’ payoffs. In this paper, the relations between some set-valued solution concepts using interval payoffs, namely the interval core, the interval dominance core, the square interval dominance core and the interval stable sets for cooperative interval games, are studied. It is shown that the interval core is the unique stable set on the class of convex interval games.     

Semicontinuity of the solution map of quasivariational inequalities

We investigate continuity properties (closedness and lower semicontinuity) of the solution map of a quasivariational inequality which is subjet to perturbations. Perturbations are here considered both on the set-valued operator and on the constraint map defining the quasivariational inequality. Two concepts of solution map will be considered.     

基于图对策的收益分配

基于具有交流结构的合作对策,即图对策,对平均树解拓展形式的特征进行刻画,提出此解满足可加性公理。进一步地,分析了对于无圈图对策此解是分支有效的。并且当连通分支中两个局中人相关联的边删掉后,此连通分支的收益变化情况可用平均树解表示。这一性质是Shapley值和Myerson值所不具有的。最后,我们给出了模糊联盟图对策中模糊平均树解的可加性和分支有效性。     

图博弈的过程比例解

本文对具有图结构合作博弈（图博弈）进行了研究，采用比例原则和过程化分配方法，定义了比例分配过程，并对其性质进行了分析。随后，针对比例分配过程的超有效情况，运用等比例妥协的方式给出满足有效性的过程比例解，并研究了稳定性。最后，将比例分配过程与过程比例解应用到破产问题中，得到图博弈过程比例解与破产问题比例规则等价的结论。     

Stability for Parametric Vector Quasi-Equilibrium Problems With Variable Cones

This article is devoted to the study of stability conditions for a class of quasi-equilibrium problems with variable cones in normed spaces. We introduce concepts of upper and lower semicontinuity of vector-valued mappings involving variable cones and their properties, we also propose a key hypothesis. Employing this hypothesis and such concepts, we investigate sufficient/necessary conditions of the Hausdorff semicontinuity/continuity for solution mappings to such problems. We also discuss characterizations for the hypothesis which do not contain information regarding solution sets. As an application, we consider the special case of traffic network problems. Our results are new or improve the existing ones.     

A dynamic solution concept for abstract games

Several solution concepts have been defined for abstract games. Some of these are the core, due to Gillies and Shapley, the Von Neumann-Morgenstern stable sets, and the subsolutions due to Roth. These solution concepts are rather static in nature. In this paper, we propose a new solution concept for abstract games, called the dynamic solution, that reflects the dynamic aspects of negotiation among the players. Some properties of the dynamic solution are studied. Also, the dynamic solution of abstract games arising fromn-person cooperative games in characteristic function form is investigated.This research was supported by the Office of Naval Research under Contract No. N00014-75-C-0678, by the National Science Foundation under Grants Nos. MPS-75-02024 and MCS-77-03984 at Cornell University, by the United States Army under Contract No. DAAG-29-75-C-0024, and by the National Science Foundation under Grant No. MCS-75-17385-A01 at the University of Wisconsin. The author is grateful to Professor W. F. Lucas under whose guidance the research was conducted.     

About Semicontinuity of Set-valued Maps and Stability of Quasivariational Inclusions

We propose several additional kinds of semi-limits and corresponding notions of semicontinuity of a set-valued map. They can be used additionally to known basic concepts of semicontinuity to have a clearer insight of local behaviors of maps. Then, we investigate semicontinuity properties of solution maps to a general parametric quasivariational inclusion, which is shown to include most of optimization-related problems. Consequences are derived for several particular problems. Our results are new or generalize/improve recent existing ones in the literature.     

Conditioning convex and nonconvex problems

Two ways of defining a well-conditioned minimization problem are introduced and related, with emphasis on the quantitative aspects. These concepts are used to study the behavior of the solution sets of minimization problems for functions with connected sublevel sets, generalizing results of Attouch-Wets in the convex case. Applications to continuity properties of subdifferentials and to projection mappings are pointed out.We are grateful to M. Valadier for pointing out, during a lecture by the author in Montpellier in October 1990 presenting the main results of the present paper, that existence results in Section 2 of the present paper can be dissociated from estimates.     

Fuzzy Optimization Problems Based on Ordering Cones

The solution concepts of the fuzzy optimization problems using ordering cone (convex cone) are proposed in this paper. We introduce an equivalence relation to partition the set of all fuzzy numbers into the equivalence classes. We then prove that this set of equivalence classes turns into a real vector space under the settings of vector addition and scalar multiplication. The notions of ordering cone and partial ordering on a vector space are essentially equivalent. Therefore, the optimality notions in the set of equivalence classes (in fact, a real vector space) can be naturally elicited by using the similar concept of Pareto optimal solution in vector optimization problems. Given an optimization problem with fuzzy coefficients, we introduce its corresponding (usual) optimization problem. Finally, we prove that the optimal solutions of its corresponding optimization problem are the Pareto optimal solutions of the original optimization problem with fuzzy coefficients.