Dolors Berga

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Please cite this article in press as: S. Barberà et al., Individual versus group strategy-proofness: When do they coincide?, Abstract A social choice function is group strategy-proof on a domain if no group of agents can manipulate its final outcome to their own benefit by declaring false preferences on that domain. There are a number of economically(More)
In the context of the provision of one pure public good, we study how large a preference domain can be to allow for the existence of strategy-proof rules satisfying the no vetoer condition. This question is qualified by the additional requirement that a domain shouldincludèà minimally rich domain.'' We first characterize generalized median voter schemes as(More)
and two anonymous referees for their helpful comments and suggestions. Abstract: We consider the problem of a society whose members must choose from a …nite set of alternatives. After knowing the chosen alternative, members may reconsider their membership by either staying or exiting. In turn, and as a consequence of the exit of some of its members, other(More)
* A previous version of this paper was entitled " Voting by Committees with Exit ". We are very grateful to the associate editor and two anonymous referees for their detailed suggestions and comments. We also thank Abstract: We study the problem of a society choosing a subset of new members from a finite set of candidates (as in Barberà, Sonnenschein, and(More)
The purpose of this paper is to discuss the extent to which allowing for individuals to be indifferent among alternatives may alter the qualitative results that are obtained in social choice theory when domain restrictions are defined on profiles of linear orders. The general message is that indifferences require attention and careful treatment, because the(More)
a r t i c l e i n f o a b s t r a c t A social choice function may or may not satisfy a desirable property depending on its domain of definition. For the same reason, different conditions may be equivalent for functions defined on some domains, while not in other cases. Understanding the role of domains is therefore a crucial issue in mechanism design. We(More)
We observe that three salient solutions to matching, division and house allocation problems are not only (partially) strategy-proof, but (partially) group strategy-proof as well, in appropriate domains of de…nition. That is the case for the Gale-Shapley mechanism, the uniform rule and the top trading cycle solution, respectively. We embed these three types(More)
We define different concepts of group strategy-proofness for social choice functions. We discuss the connections between the defined concepts under different assumptions on their domains of definition. We characterize the social choice functions that satisfy each one of them and whose ranges consist of two alternatives, in terms of two types of basic(More)