Ted, James (and anyone interested), In my last post (Thu.May5) I suggested this criterion: "If x wins, and afterwards some identical ballots that approve x are uniformly changed only so that they approve more candidates than previously; then if there is a new winner it must be one of the candidates approved on these altered ballots."
This is supposed to be a simple test for the property that approving more candidates should never change the winner from an approved (on the original ballots) candidateto a disapproved (on both sets of ballots) candidate. This is very similar to this monotonicity-like criterion: "If x wins, and afterwards some ballots are changed only to increase the approval scores of some other candidates; then if there is new winner it must be one of the candidates whose approval scores have been raised." Or maybe it is better to put it the other way: "If x wins, and afterwards some ballots are changed only to decrease the approval scores of one or more other candidates; then x must still win." Yes, this seems more succinct. But what to call it, "Mono-reduce opposition approval"? Another criterion that applies to rankings/approval methods interests me, which I might call "Disapproval Later-no-Harm": "Ranking a disapproved candidate must never harm an approved candidate". (A stronger version would add "or a higher-ranked disapproved candidate"). This is incompatible with Condorcet, and in a future post I'll suggest a method that meets it. Chris Benham Find local movie times and trailers on Yahoo! Movies. http://au.movies.yahoo.com ---- Election-methods mailing list - see http://electorama.com/em for list info
