On the equivalence of coalitional and individual strategy-proofness properties

In this paper, we introduce a su¢ cient condition on the domain of admissible preferences of a social choice mechanism under which the properties of individual and coalitional strategyproofness are equivalent. Then, we illustrate the usefulness of this general result in the case where a …xed budget has to be allocated among several pure public goods. Université de Toulouse 1, Gremaq and Idei, France ([email protected]) yUniversité de Toulouse 1, Gremaq, France and Université Catholique de Louvain, Core, Belgium ([email protected]).