The Shapley value of coalitions to other coalitions

International Journal of Game Theory, 2012

We consider an alternative expression of the Shapley value that reveals a system of compensations: each player receives an equal share of the worth of each coalition he belongs to, and has to compensate an equal share of the worth of any coalition he does not belong to. We give an interpretation in terms of formation of the grand coalition according to an ordering of the players and define the corresponding compensation vector. Then, we generalize this idea to cooperative games with a communication graph. Firstly, we consider cooperative games with a forest (cycle-free graph). We extend the compensation vector by considering all rooted spanning trees of the forest (see Demange ) instead of orderings of the players. The associated allocation rule, called the compensation solution, is characterized by component efficiency and relative fairness. The latter axiom takes into account the relative position of a player with respect to his component. Secondly, we consider cooperative games with arbitrary graphs and construct rooted spanning trees by using the classical algorithms DFS and BFS. If the graph is complete, we show that the compensation solutions associated with DFS and BFS coincide with the Shapley value and the equal surplus division respectively.

Fuzzy Sets and Systems, 2019

This paper deals with cooperative games over fuzzy coalitions. In these situations there is a continuous set of fuzzy coalitions instead of a finite set of them (as in the classical case), the unit square in an n-dimensional space. There exist in the literature two different extensions of the known Shapley value for crisp games to games with fuzzy coalitions: the crisp Shapley value and the diagonal value. The first value only uses a finite information in the set of fuzzy coalitions, the vertices of the square. While the second one uses a neighbourhood of the diagonal of the square. We propose a new extension of the Shapley value improving the crisp Shapley value for games with fuzzy coalitions. This new version uses the faces of the square, namely an infinity quantity of information. We analyze several properties of the new value, we endow it with an axiomatization and we study the behavior when it is applied to known fuzziness of crisp games.

TOP, 2008

In this paper a simple probabilistic model of coalition formation provides a uni ed interpretation for several extensions of the Shapley value. Weighted Shapley values, semivalues, and weak (weighted or not) semivalues, and the Shapley value itself appear as variations of this model. Moreover, some notions that have been introduced in the search of alternatives to Shapley's seminal characterization, as 'balanced contributions' and the 'potential' are reinterpreted from this point of view. The natural relationships of these conditions with some the mentioned families of 'values' are shown. These reinterpretations strongly suggest that these conditions are more naturally interpreted in terms of coalition formation than in terms of the classical notion of 'value'.

2006

The Shapley value provides a unique solution to coalition games and is used to evaluate a player's prospects of playing a game. Although it provides a unique solution, there is an element of uncertainty associated with this value. This uncertainty in the solution of a game provides an additional dimension for evaluating a player's prospects of playing the game. Thus, players want to know not only their Shapley value for a game, but also the associated uncertainty. Given this, our objective is to determine the Shapley value and its uncertainty and study the relationship between them for the voting game. But since the problem of determining the Shapley value for this game is #P-complete, we first present a new polynomial time randomized method for determining the approximate Shapley value. Using this method, we compute the Shapley value and correlate it with its uncertainty so as to allow agents to compare games on the basis of both their Shapley values and the associated uncertainties. Our study shows that, a player's uncertainty first increases with its Shapley value and then decreases. This implies that the uncertainty is at its minimum when the value is at its maximum, and that agents do not always have to compromise value in order to reduce uncertainty.

Social Choice and Welfare, 2001

ABSTRACT The article decomposes the Shapley value into a value matrix which gives the value of every player to every other player in n-person games. Element ij(v) in the value matrix is positive, zero, or negative, dependent on whether row player i is beneficial, has no impact, or is not beneficial for column player j. The elements in each row and in each column of the value matrix sum up to the Shapley value of the respective player. The value matrix is illustrated by the voting procedure in the European Council of Ministers 1981-1995.

2004

and centrA: RESUMEN El objetivo de este trabajo es analizar un concepto de solución que asigna a cada juego bicooperativo un único vector. En el contexto de los juegos bicooperativos introducidos por Bilbao (2000), definimos una solución denominada valor de Shapley porque este valor puede interpretarse de una ma nera semejante al clásico valor de Shapley para juegos cooperativos. El resultado más importante del trabajo es una caracterización axiomática de este valor.

2017

We present a general bargaining protocol between n players in the setting of coalitional games with transferable utility. We consider asymmetric players. They are endowed with di¤erent probabilities of being chosen as proposers and with di¤erent probabilities of leaving the game if o¤ers are rejected. Two particular speci…cations of this bargaining protocol yield equilibrium proposals that we refer to as weighted solidarity values and weighted Shapley values. We compare the behavior of these values when the players’ probabilities are changed. We supplement the analysis with axiomatic characterizations of both values.

2006

Bi-cooperative games have been introduced by Bilbao as a generalization of classical cooperative games, where each player can participate positively to the game (defender), negatively (defeater), or do not participate (abstentionist). In a voting situation (simple games), they coincide with ternary voting game of Felsenthal and Mochover, where each voter can vote in favor, against or abstain. In this paper, we propose a definition of value or solution concept for bi-cooperative games, close to the Shapley value, and we give an interpretation of this value in the framework of (ternary) simple games, in the spirit of Shapley-Shubik, using the notion of swing. Lastly, we compare our definition with the one of Felsenthal and Machover, based on the notion of ternary roll-call, and the Shapley value of multi-choice games proposed by Hsiao and Ragahavan.

Mathematical Social Sciences, 2010

A new axiomatic characterization of the two-step Shapley value Kamijo ( ) is presented based on a solidarity principle of the members of any union: when the game changes due to the addition or deletion of players outside the union, all members of the union will share the same gains/losses.

Mathematical Social Sciences, 2008

The main focus of this paper is on the restricted Shapley value for multi-choice games introduced by Derks and Peters . A Shapley value for games with restricted coalitions. International Journal of Game Theory 21, 351-360] and studied by Klijn et al. [Klijn, F., Slikker, M., Zazuelo, J., 1999.

2010

We consider the issue of representing coalitional games in multiagent systems that exhibit externalities from coalition formation, i.e., systems in which the gain from forming a coalition may be affected by the formation of other co-existing coalitions. Although externalities play a key role in many real-life situations, very little attention has been given to this issue in the multi-agent system literature, especially with regard to the computational aspects involved. To this end, we propose a new representation which, in the spirit of Ieong and Shoham , is based on Boolean expressions. The idea behind our representation is to construct much richer expressions that allow for capturing externalities induced upon coalitions. We show that the new representation is fully expressive, at least as concise as the conventional partition function game representation and, for many games, exponentially more concise. We evaluate the efficiency of our new representation by considering the problem of computing the Extended and Generalized Shapley value, a powerful extension of the conventional Shapley value to games with externalities. We show that by using our new representation, the Extended and Generalized Shapley value, which has not been studied in the computer science literature to date, can be computed in time linear in the size of the input.

Frontiers in applied mathematics and statistics, 2024

The core and the Shapley value stand out as the most renowned solutions for addressing sharing problems in cooperative game theory. These concepts are widely acknowledged for their e ectiveness in tackling negotiation, resource allocation, and power dynamics. The present study aims to extend various notions of cooperative games from the standard set N to a new class of cooperative games defined on the cartesian product N × N ′ (utilizing the specific coalition A * B). This extension encompasses fundamental concepts such as rationality, core, and Shapley value. The findings presented in this study demonstrate that the core concept as a solution yields a set of imputations without favoring any specific point within the set, in contrast to the Shapley value, which o ers a singular solution. Moreover, the results confirm that the Shapley value satisfies the conditions defining the core of a game. Through both theoretical analysis and numerical findings, employing a practical example, it becomes evident that the Shapley value o ers a more distinct solution to the sharing problem compared with the core solution.

Games and Economic Behavior, 2013

Assuming a 'spectrum' or ordering of the players of a coalitional game, as in a political spectrum in a parliamentary situation, we consider a variation of the Shapley value in which coalitions may only be formed if they are connected with respect to the spectrum. This results in a naturally asymmetric power index in which positioning along the spectrum is critical. We present both a characterisation of this value by means of properties and combinatoric formulae for calculating it. In simple majority games, the greatest power accrues to 'moderate' players who are located neither at the extremes of the spectrum nor in its centre. In supermajority games, power increasingly accrues towards the extremes, and in unaninimity games all power is held by the players at the extreme of the spectrum.

Cybernetics and Systems Analysis, 2017

The paper investigates Shapley value of a cooperative game with fuzzy set of feasible coalitions. It is shown that the set of its values is a type 2 fuzzy set (a fuzzy set whose membership function takes fuzzy values) of special type. Furthermore, the corresponding membership function is given. Elements of the support of this set are defined as particular Shapley values. The authors also propose the procedure of constructing these elements with maximum reliability of their membership and reliability of non-membership, not exceeding a given threshold.

2007

The Shapley value is one of the key solution concepts for coalition games. Its main advantage is that it provides a unique and fair solution, but its main problem is that, for many coalition games, the Shapley value cannot be determined in polynomial time. In particular, the problem of finding this value for the voting game is known to be #P-complete in the general case. However, in this paper, we show that there are some specific voting games for which the problem is computationally tractable. For other general voting games, we overcome the problem of computational complexity by presenting a new randomized method for determining the approximate Shapley value. The time complexity of this method is linear in the number of players. We also show, through empirical studies, that the percentage error for the proposed method is always less than 20% and, in most cases, less than 5%.