Resumen de Triple-consistent social choice and the majority rule

Gilbert Laffond, Jean Lainé

• We define generalized (preference) domains D as subsets of the hypercube {−1,1} D , where each of the D coordinates relates to a yes-no issue. Given a finite set of n individuals, a profile assigns each individual to an element of D . We prove that, for any domain D , the outcome of issue-wise majority voting φ m belongs to D at any profile where φ m is well-defined if and only if this is true when φ m is applied to any profile involving only 3 elements of D . We call this property triple-consistency. We characterize the class of anonymous issue-wise voting rules that are triple-consistent, and give several interpretations of the result, each being related to a specific collective choice problem.