Nous aurons le plaisir d'entendre un exposé d'Ulle Endriss (ILLC, University of Amsterdam), intitulé : "Collective Rationality in Graph Aggregation"
Résumé : Suppose a number of agents each provide us with a directed graph over a common set of vertices. Graph aggregation is the problem of computing a single "collective" graph that best represents the information inherent in this profile of individual graphs. For example, we might want to aggregate different social networks, abstract argumentation frameworks, clusterings of data, preferences, or entailment relations defining different logical systems, all of which can be modeled as graphs. In this talk, I will consider the graph aggregation problem from the point of view of social choice theory and ask what properties shared by the individual graphs will transfer to the graph returned by a given aggregation rule. The main result I will present is a general impossibility theorem that applies to a wide range of graph properties.