Dictatorial voting operators

Abstract

Voting operators map n-tuples of subsets of a given set X of candidates (the voters’ choices) into subsets of X (the social choice). This paper characterizes dictatorial voting operators by means of three conditions (the non-emptiness condition A1, the independence condition A2 and the resoluteness condition A3) motivated by the idea of transferring to the social choice properties common to all the voters’ choices. The result is used to refine Lahiri’s (2001) characterization and to derive dictatorial results in other three types of aggregation problems, in which choice functions are transformed into choice functions, binary relations into choices and binary relations into binary relations.