[EM] AERLO loses any FBC. MMPO is Approval. Still the best public method.
stepjak at yahoo.fr
Sun Jun 19 14:59:17 PDT 2005
--- MIKE OSSIPOFF <nkklrp at hotmail.com> a écrit :
> And when, with that method, in an acceptable/unacceptable situation, a voter
> uses his/her best strategy, protecting the acceptable candidates by AERLO
> and power truncation, then MMPO with power truncation becomes identical with
> Approval for that voter.
> CR, when voters use their best strategy, also becomes identical to Approval.
> Maybe that's true of all FBC-complying methods. Forest and Kevin, why not
> check out the other FBC-complying methods, such as tMMWV and the other
> t methods described by Kevin. And like the Ordered-Bucklin variant that
> Forest described, if it meets FBC.
Well, as far as "tC//A," or "Improved Condorcet Approval," I don't believe that
the optimal strategy is to only use the extremes. If you vote A>B, and this
causes B to fail to be the CW, then your vote is compressed and you automatically
vote for both A and B equally. B has a pretty good chance of still winning. B
might ultimately lose, but you do obtain the opportunity to have A win instead
of supporting A and B equally from the start.
If you're talking about a voter in an acceptable/unacceptable situation, then
probably he won't bother to use lower ranks. It seems like a tall order to
get around this...
Assume that the voter just has some candidates he wants to rank, and some
he doesn't. A nice criterion would say that no shuffling of the ranked candidates
can cause the win to move from a ranked candidate to an unranked candidate, or
(obviously) vice versa. But I can't think what would satisfy this criterion other
than Approval with a ranking stapled to it.
> How good properties and criterion compliances can be offered by
> FBC-complying rank methods, with and without enhancements? So far MMPO has
> been discussed. I'm suggesting that Forest and Kevin discuss some of the
> other FBC-complying rank methods.
tC//A aka ICA satisfies Plurality, Minimal Defense (if using a fully ranked ballot),
SDSC (ditto), FBC, and Monotonicity. It fails Condorcet (technically), Participation,
LNHarm, and Clone-Winner.
I currently wonder whether SDSC, FBC, and Clone-Winner are compatible in a
method more complicated than Approval.
It's possible to define a weakened version of Condorcet which ICA would satisfy:
"If there is at least one candidate X such that for any other candidate Y,
v[x,y]+t[x,y]>=v[y,x], then one such candidate must be elected."
Oddly, Condorcet doesn't imply this "weak" Condorcet. Also, this "weak" Condorcet
seems incompatible with Clone-Winner.
Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! Messenger
Téléchargez cette version sur http://fr.messenger.yahoo.com
More information about the Election-Methods