Résumé en anglais

In a voting system, voters may adopt a strategic behaviour in order to manipulate the outcome of the election. This naturally entails a game theoretic conception of voting. The specificity of our work is that we embed the voting game into a social context where agents and their relations are given by a graph, i.e. a social network. We aim at integrating the information provided by the graph in a refinement of the game-theotical analysis of an election. We consider coalitional equilibria immune to deviations performed by realistic coalitions based on the social network, namely the cliques of the graph. Agents are not fully selfish as they have consideration for their relatives. The corresponding notion of equilibrium was introduced by Hoefer et al. [12] and called considerate equilibrium. We propose to study its existence and the ability of the agents to converge to such an equilibrium in strategic voting games using well-known voting rules: Plurality, Antiplurality, Plurality with runoff, Borda, k-approval, STV, Maximin and Copeland.