2009/6/7 Raph Frank <[email protected]> > On Sun, Jun 7, 2009 at 7:35 PM, Árpád Magosányi <[email protected]> wrote: > >> """" >> - The electors rank the candidates according to their preferences. >> - If there is a group of candidates all preferred over all candidates >> outside the group, then ignoring the candidates outside the group should not >> change the outcome of the election. >> - The winner should be choosen from the above group in a way that >> guarantees that if a candidate similar to an already running candidate is >> introduced, the outcome of the election is not changed, and the less >> controversial candidates are preferred. >> """ >> > > > Ok, so you are basically saying (in simple terms) > > A) the method is a ranked method > B) All candidates outside the Smith set can be ignored without changing the > result > C) The method should be clone independent. >
Not exactly. C/1) The method should be clone independent C/2) The method should prefer weak defeats Actually C/2 is the one where I yet to became confident that there is a one-to-one match between the wording and the exact mathematical definition. [...] > > Schulze and ranked pairs are the only methods that meet clone independence > and the condorcet rule. > > Does ranked pairs fail the Smith criterion? > No. It fails the prefer-weak-defeats criterion only from the above. > > > I would change B to "If there is a group of candidates all preferred over > all candidates outside the group, then only those candidates may win and the > candidates outside the group may have no effect on the result". > > If you don't restrict the winner to the Smith set (which your rules don't > necessarily), then you could end up with a non-condorcet method. > B does restrict the winner to the Smith set. If someone outside the Smith set wins, ignoring him would change the election result. > > > Also, just because the popular/proposed condorcet methods are excluded by > your definition doesn't mean that some other weird method can't be found > that also meets the rule. > This is why I have put clone independence back. > > > It might be better to just include the reasons that you like Sculze and use > those rules rather than trying to select Sculze by a process of elimination. > Actually I end up doing so. I did not include monotonicity because I don't view it as very important, but include cloneproofness because I do. (I am hoping that a nonmonotonic method matching all other criteria should not be very bad in most cases.)
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