[EM] Combing Reweighted range/score voting and PR-STV

Raph Frank raphfrk at gmail.com
Wed Aug 19 05:51:22 PDT 2009


On Wed, Aug 19, 2009 at 7:19 AM, Kristofer
Munsterhjelm<km-elmet at broadpark.no> wrote:
> That might be true, yes... If we have sets of the form:
>
> 1 DQ + 2: {A B C D}
> 1 DQ + 1: {E F}
>
> then we shouldn't keep picking from the first to fill the council, because
> once they've got their candidate, they should have no more. One could patch
> this by noting how many have already been elected from that group, like:
>
> 1 DQ + 2: {A B C D} 0
> 1 DQ + 1: {E F}     0
>
> then A is elected and
>
> 1 DQ + 2: {B C D}   1 <-- got our fill
> 1 DQ + 1: {E F}     0 <-- pick from here!

That is kinda like what PR-STV already does, at least in the first round.

If a Droop quota prefer candidate A to all other candidates, then he
will get a Droop quota worth of first choices and automatically be
elected.

This could be generalised.

Round 2 might look at all 2 candidate sets.  If a Droop quota of
voters prefer a set of candidates to all other candidates, then one of
that set must win.


For example,

60: A1>A2>B1>B2
20: B1>B2>A1>A2
20: B2>B1>A1>A2

and 3 seats

Round 1
60: A1>All
0: A2>All
20: B1>All
20: B2>All

So A1 meets quota, thus "A1 must be in winning set" added as condition.

Round 2:
60: [A1,A2] > All
40: [B1,B2] > All
(plus some others which are supported by 0

So,
[A1,A2] meets 2*quota, so A2 can also be added as a winner
[B1,B2] meets 1 quota, so "B1 or B2 must be a winner" is added as a condition.


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