Consistent Linear Orders for Supermajority Rules

Abstract

We consider linear orders of finite alternatives that are constructed by aggregating the preferences of individuals. We focus on a linear order that is consistent with the collective preference relation, which is constructed by one of the supermajority rules and modified using two procedures if there exist some cycles. One modification procedure uses the transitive closure, and the other uses the Suzumura consistent closure. We derive two sets of linear orders that are consistent with the (modified) collective preference relations formed by any of the supermajority rules. These sets of linear orders are closely related to those obtained through Tideman's ranked pairs method and the Schulze method. Finally, we consider two social choice correspondences whose output is one of the sets introduced above, and show that the correspondences satisfy the four properties: the extended Condorcet principle, the Pareto principle, the independence of clones, and the reversal symmetry