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Michel Grabisch has fully succeeded in transforming his deep knowledge of the field into a very rich and quite readable text. Professor Denis Bouyssou, Université Paris Dauphine This monograph provides a much-needed perspective on a rich collection of structural properties of set functions which have been investigated for more than 60 years, but which have never been collected in a single volume. By establishing these results in a clear and rigorous mathematical framework, the author makes them accessible to a broad audience. His book should rapidly become a classic reference in the field. Professor Yves Crama, University of Liège and HEC Liège This book is an excellent compendium of technical notions pertaining to set functions, that are relevant in uncertainty management, game theory, and multicriteria decision-making. It will be a very useful companion to any student or researcher willing to investigate these fields beyond standard probability theory and simple additive methods. Professor Didier Dubois, IRIT, Université Paul Sabatier, Toulouse In this book, written by a leading scholar, the readers can finally find a unified and comprehensive study of set functions. It is a much needed, beautiful, book that will be most useful to the cognoscenti, who will appreciate its depth and breadth, as well as to the readers who desire to learn about this fundamental topic. Professor Massimo Marinacci, Università Bocconi Nonadditive set functions are used in many optimization and decision theories (uncertain, fuzzy, multi-criteria, strategic, AI, combinatorial, statistical, ...), many developing the same results independently. The only person knowing all these fields brought it all together and improved it brilliantly in this well-focused book. It is a must for anyone using set functions. Professor Peter P. Wakker, Erasmus University Rotterdam.

AbstractWe address in this paper the problem of scoring alternatives when they are evaluated with respect to several criteria on a finite ordinal scale E. We show that in general, the ordinal scale E has to be refined or shrunk in order to be able to represent the preference of the decision maker by an aggregation operator belonging to the family of mean operators. This paper recalls previous theoretical results of the author giving necessary and sufficient conditions for a representation of preferences, and then focuses on describing practical algorithms and examples. Copyright © 2008 John Wiley & Sons, Ltd.

AbstractWe provide a detailed study of the threshold model, where both conformist and anti-conformist agents coexist. Our study bears essentially on the convergence of the opinion dynamics in the society of agents, i.e., finding absorbing classes, cycles, etc. Also, we are interested in the existence of cascade effects, as this may constitute an undesirable phenomenon in collective behavior. We divide our study into two parts. In the first one, we basically study the threshold model supposing a fixed complete network, where every one is connected to every one, like in the seminal work of Granovetter. We study the case of a uniform distribution of the threshold, of a Gaussian distribution, and finally give a result for arbitrary distributions, supposing there is one type of anti-conformist. In a second part, we suppose that the neighborhood of an agent is random, drawn at each time step from a distribution. We distinguish the case where the degree (number of links) of an agent is fixed, and where there is an arbitrary degree distribution. We show the existence of cascades and that for most societies, the opinion converges to a chaotic situation.

International audience In this paper we give representation results about the calculation of the Choquet integral of a monotone function on the nonnegative real line. Next, we represent the Choquet integral of nonmonotone functions, by construction of monotone functions from nonmonotone ones, by using the increasing and decreasing rearrangement of a nonmono-tone function. Finally, this paper is completed with some applications of these results to the continuous agregation operator OWA, and to the representation of risk measures by Choquet integral.

International audience ; The paper concerns a dynamic model of influence in which agents make a yes-no decision. Each agent has an initial opinion which he may change during different phases of interaction, due to mutual influence among agents. We investigate a model of influence based on aggregation functions. Each agent modifies his opinion independently of the others, by aggregating the current opinion of all agents. Our framework covers numerous existing models of opinion formation, since we allow for arbitrary aggregation functions. We provide a general analysis of convergence in the aggregation model and find all terminal classes and states. We show that possible terminal classes to which the process of influence may converge are terminal states (the consensus states and non trivial states), cyclic terminal classes, and unions of Boolean lattices (called regular terminal classes). An agent is influential for another agent if the opinion of the first one matters for the latter. A generalization of influential agent to an irreducible coalition whose opinion matters for an agent is called influential coalition. The graph (hypergraph) of influence is a graphical representation of influential agents (coalitions). Based on properties of the hypergraphs of influence we obtain conditions for the existence of the different kinds of terminal classes. An important family of aggregation functions -- the family of symmetric decomposable models -- is discussed. Finally, based on the results of the paper, we analyze the manager network of Krackhardt.

International audience ; The classical Shapley value is the average marginal contribution of a player, taken over all possible ways to form the grand coalition $N$ when one starts from the empty coalition and adds players one by one. In a previous paper, the authors have introduced an allocation scheme for a general coalition formation model where the evolution of the coalition of active players is ruled by a Markov chain and need not finish with the grand coalition. This note provides an axiomatization which is only slightly weaker than the original one but allows a much more transparent proof. Moreover, the logical independence of the axioms is exhibited.

International audience ; The classical Shapley value is the average marginal contribution of a player, taken over all possible ways to form the grand coalition $N$ when one starts from the empty coalition and adds players one by one. In a previous paper, the authors have introduced an allocation scheme for a general coalition formation model where the evolution of the coalition of active players is ruled by a Markov chain and need not finish with the grand coalition. This note provides an axiomatization which is only slightly weaker than the original one but allows a much more transparent proof. Moreover, the logical independence of the axioms is exhibited.

International audience ; The classical Shapley value is the average marginal contribution of a player, taken over all possible ways to form the grand coalition $N$ when one starts from the empty coalition and adds players one by one. In a previous paper, the authors have introduced an allocation scheme for a general coalition formation model where the evolution of the coalition of active players is ruled by a Markov chain and need not finish with the grand coalition. This note provides an axiomatization which is only slightly weaker than the original one but allows a much more transparent proof. Moreover, the logical independence of the axioms is exhibited.

International audience ; The paper concerns a dynamic model of influence in which agents make a yes-no decision. Each agent has an initial opinion which he may change during different phases of interaction, due to mutual influence among agents. We investigate a model of influence based on aggregation functions. Each agent modifies his opinion independently of the others, by aggregating the current opinion of all agents. Our framework covers numerous existing models of opinion formation, since we allow for arbitrary aggregation functions. We provide a general analysis of convergence in the aggregation model and find all terminal classes and states. We show that possible terminal classes to which the process of influence may converge are terminal states (the consensus states and non trivial states), cyclic terminal classes, and unions of Boolean lattices (called regular terminal classes). An agent is influential for another agent if the opinion of the first one matters for the latter. A generalization of influential agent to an irreducible coalition whose opinion matters for an agent is called influential coalition. The graph (hypergraph) of influence is a graphical representation of influential agents (coalitions). Based on properties of the hypergraphs of influence we obtain conditions for the existence of the different kinds of terminal classes. An important family of aggregation functions -- the family of symmetric decomposable models -- is discussed. Finally, based on the results of the paper, we analyze the manager network of Krackhardt.

International audience ; The classical Shapley value is the average marginal contribution of a player, taken over all possible ways to form the grand coalition $N$ when one starts from the empty coalition and adds players one by one. In a previous paper, the authors have introduced an allocation scheme for a general coalition formation model where the evolution of the coalition of active players is ruled by a Markov chain and need not finish with the grand coalition. This note provides an axiomatization which is only slightly weaker than the original one but allows a much more transparent proof. Moreover, the logical independence of the axioms is exhibited.