Characterizations of approval ranking

In this paper, we consider those voting situations in which each voter decides whether he or she approves each candidate. Given a list of such approvals, a “social preference function” picks a ranking of the candidates. We are interested in finding out which social preference functions are non-manipulable. We show that a particular social preference function, referred to as approval ranking, is more decisive than any other social preference functions satisfying completeness, neutrality, anonymity, and non-manipulability. In addition, we show that approval ranking is axiomatized by these four axioms and tie-breakability.