Unrestricted domain: Difference between revisions

The Universality criterion is part of the proof of [[Arrow's impossiblility theorem]], which statesrequires that a system givesgive unique results for a given set of ranked ballots. ThisIt was stated by Kenneth Arrow as part of his [[Arrow's impossiblility theorem|impossiblity theorem]], and it is such a basic criterion that it is's satisfied by all non-random ranked systems. However, since it was defined by Kenneth Arrow before there had been theoretical analysis of rated voting systems, it does not apply to rated ballots, and so all rated systems technically violate universality. This is why some rated systems, such as [[MCA|MCA-P]], can appear to violate Arrow's theorem by satisfying all of his more-interesting criteria. Without (ranked) universality, those other criteria are not incompatible.