ACYCLIC SOCIAL CHOICE FROM FINITE SETS

This paper characterizes acyclic preference aggregation rules under va rious combinations of monotonicity, neutrality, decisiveness, and anon ymity, in the spirit of Nakamura's (1979) Theorem on the core of simpl e games. Each of these characterizations can be seen to follow from Fe rejohn and Fishburn's (1979) result on acyclic aggregation rules assum ing only independence of irrelevant alternatives. We then state as cor ollaries to these characterizations extant results such as Sen's (1970 ) liberal paradox, Blau and Deb's (1977) theorem on the existence of v etoers, and Brown's (1975) theorem on the non-emptiness of the collegi um.