A characterization of pairwise dictatorial approbatory social welfare functions

Abstract

[EN] This paper defines approbatory social welfare functions. They are the natural counterpart of Arrovian social welfare functions when the expression of preferences is accompanied by a common choice of “approved” alternatives in a consistent manner. First, we count the number of consistent preference-approval profiles (the domain of approbatory social welfare functions). Then we show that pairwise dictatorial behaviors are characterized by unanimity and independence of irrelevant alternatives, a replication of Arrow’s characterization of dictatorships for this restricted version of the preference-approval model defined by Brams and Sanver in 2009.