[EM] proportional constraints - help needed
Juho Laatu
juho4880 at yahoo.co.uk
Mon Feb 11 17:33:03 PST 2013
On 12.2.2013, at 1.24, Jameson Quinn wrote:
> 2013/2/11 Kristofer Munsterhjelm <km_elmet at lavabit.com>
> (Also, speaking of criteria: if I had enough time, I would try to find a monotone variant of Schulze STV. I think one can make monotone Droop-proportional multiwinner methods, since I made a Bucklin hack that seemed to be both monotone and Droop-proportional. However, I have no mathematical proof that the method obeys both criteria.)
>
> What does monotone even mean for PR? You can make something that's sequentially monotone, but it's (I think) impossible to avoid situations where AB were winning but changing C>A>B to A>B>C causes B to lose (or variants of this kind of problem). That's still technically "monotone", but from a voters perspective, it's not usefully so.
I think monotonicity is sometimes an obvious requirement but not always. A ranked ordering (=> monotonicity with respect to adding seats) may give different results than a proportional algorithm that just picks the agreed number of representatives (with no order). Sometimes a ranked ordering is needed (like in the Czech Green Party canddidate list), sometimes not. The need to establish a ranked order may make the proportionality of the results slightly worse.
I also like the Alabama paradox in the sense that one can as well consider such results the correct and exact outcome, not a "negative paradox". All in all, both appraches are needed, for different needs.
Juho
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20130212/cdf201ec/attachment-0004.htm>
More information about the Election-Methods
mailing list