Implementation Via Approval Mechanisms

Matias Nunez (1) , Dimitrios Xefteris (2)

1 LAMSADE - Laboratoire d'analyse et modélisation de systèmes pour l'aide à la décision
2 University of Cyprus = Université de Chypre

We focus on the single-peaked domain and study the class of Generalized Approval Mechanisms (GAMs): First, players simultaneously select subsets of the outcome space and scores are assigned to each alternative; and, then, a given quantile of the induced score distribution is implemented. Our main finding is that essentially for every Nash-implementable welfare optimum – including the Condorcet winner alternative – there exists a GAM that Nash-implements it. Importantly, the GAM that Nash-implements the Condorcet winner alternative is the first simple simultaneous game with this feature in the literature.

Mots clés: Nash Implementation; Strategy-proofness; Approval Voting; Single-Peakedness; Condorcet winner

Domaines: Informatique [cs]

Matias Nunez, Dimitrios Xefteris. Implementation Via Approval Mechanisms. Journal of Economic Theory, 2017, 170, ⟨10.1016/j.jet.2017.05.003⟩. ⟨hal-01715095⟩