Unanimous Implementation: A Case for Approval Mechanisms

25 Pages Posted: 7 Feb 2016 Last revised: 1 Jul 2016

See all articles by Matias Nuñez

Matias Nuñez

Université Paris Dauphine

Dimitrios Xefteris

University of Cyprus

Date Written: June 30, 2016


We design the class of (indirect) Approval mechanisms which allow the players' strategies to coincide with the subsets of the outcome space. By focusing on the single-peaked domain, we prove that: a) Each of these mechanisms is characterized by a unique equilibrium outcome, and b) for almost every implementable welfare optimum (outcome of a social choice rule), including the Condorcet winner alternative, there exists an Approval mechanism that unanimously implements it. That is, Approval mechanisms help a society achieve every feasible welfare goal, and, perhaps more importantly, they promote social coherence: The implemented outcome is approved by everyone.

Keywords: Nash Implementation, Strategy-proof, Unanimity, Indirect Mechanisms

JEL Classification: C9, D71, D78, H41

Suggested Citation

Nuñez, Matias and Xefteris, Dimitrios, Unanimous Implementation: A Case for Approval Mechanisms (June 30, 2016). Available at SSRN: https://ssrn.com/abstract=2728337 or http://dx.doi.org/10.2139/ssrn.2728337

Matias Nuñez (Contact Author)

Université Paris Dauphine ( email )

Place du Maréchal de Tassigny
Paris, Cedex 16 75775

Dimitrios Xefteris

University of Cyprus ( email )

75 Kallipoleos Street
P.O. Box 20537
1678 Nicosia

Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Abstract Views
PlumX Metrics