Jordi Massó

We consider the problem of a society that uses a voting rule to choose a subset from a given set of objects (candidates, binary issues, or alike). We assume that voters’ preferences over subsets of objects are separable: adding an object to a set leads to a better set if and only if the object is good (as a singleton set, the object is better than the empty set). A voting rule is strategy-proof if no voter benefits by not revealing its preferences truthfully and it is false-name-proof if no voter benefits by submitting several votes under other identities. We characterize all voting rules that satisfy false-name-proofness, strategy-proofness, and ontoness as the class of voting rules in which an object is chosen if it has either at least one vote in every society or a unanimous vote in every society. To do this, we first prove that if a voting rule is false-name-proof, strategy-proof, and onto, then the identities of the voters are not important.

En las últimas décadas, dos líneas de pensamiento han querido hacerse cargo de la necesidad de pensar “lo común” desde coordenadas ontológicas. Una, representada principalmente por Jean-Luc Nancy y Alain Badiou, retoma los análisis de Heidegger sobre el Mitsein; la otra parte de los análisis que Toni Negri hace de la noción de “multitud” de Spinoza. Estas dos “ontologías de lo común” han dado pie a sendas estéticas que persiguen una finalidad política. Este trabajo estudia estas tendencias con el fin de determinar qué tipo de noción de “lo común” manejan. La tesis esgrimida es la de que la interpretación que hacen de aquellas ontologías es errónea y que la “comunidad” presente en ellas está más próxima al sensus communis kantiano.

We study how to partition a set of agents in a stable way when each coalition in the partition has to share a unit of a perfectly divisible good, and each agent has symmetric single-peaked preferences on the unit interval of his potential shares. A rule on the set of preference profiles consists of a partition function and a solution. Given a preference profile, a partition is selected and as many units of the good as the number of coalitions in the partition are allocated, where each unit is shared among all agents belonging to the same coalition according to the solution. A rule is stable at a preference profile if no agent strictly prefers to leave his coalition to join another coalition and all members of the receiving coalition want to admit him. We show that the proportional solution and all sequential dictator solutions admit stable partition functions. We also show that stability is a strong requirement that becomes easily incompatible with other desirable properties like efficiency, strategy-proofness, anonymity, and non-envyness.