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<font face="Helvetica, Arial, sans-serif">Michael - I don't think I
understand everything you're saying. I was referring to RP
(margins), which I believe is the form in which Tideman specified
it, and I assumed that truncation was a mixture of laziness and
ignorance. (Actually the simulation I referred to assumed
mandatory truncation, which I think is common in the US.) I don't
hold any brief for RP; on the contrary I much prefer minimax (also
margins). <br>
I do indeed think that voters will have difficulty in
rank-ordering lots of candidates, or even in examining and
choosing between them. I hoped that the primary I proposed would
make the best of voters who were unable to assess the entire
field, since if they voted for someone they'd heard of, and that
candidate got eliminated, then their vote would be transferred to
someone they might like, even if they didn't realise it. <br>
Colin</font><br>
<br>
<div class="moz-cite-prefix">On 17/09/2023 06:42, Michael Ossipoff
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAOKDY5AUHK+CE-oDduGi78jtVBOz+NXhWHbAtmk_x4=e19aGig@mail.gmail.com">
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<div dir="auto">Is that RP(wv), or RP(margins) ?</div>
<div dir="auto"><br>
</div>
<div dir="auto">RP(wv) would thwart & deter offensive
strategy, an important property in public elections.</div>
<div dir="auto"><br>
</div>
<div dir="auto">…&, actually, it seems to me that MinMax(wv)
would do that better.</div>
<div dir="auto"><br>
</div>
<div dir="auto">That’s because, choosing only from the Smith Set
RP, limits it’s choice to the strategic top-cycle that created
by the offensive strategists.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Suppose that the CW’s preferrers don’t do
defensive truncation (never rank anyone you wouldn’t approve in
Approval, or whose preferrers you regard as likely to
offensively order-reverse) ?</div>
<div dir="auto"><br>
</div>
<div dir="auto">Knowing that RP will limit its choice to their
small strategic top-cycle, it would be easier for the
strategists to be fairly sur that their candidate would win in
that top-cycle.</div>
<div dir="auto"><br>
</div>
<div dir="auto">But, with MinMax, the winner is chosen more
broadly, & could be anywhere in the candidate-set. …making
it more difficult & risky to confidently do offensive
order/reversal.</div>
<div dir="auto"><br>
</div>
<div dir="auto">RP(margins) might the best choice for a completely
honest electorate, but MinMax(wv) seems better for public
elections, due to its better thwarting & deterrence of
offensive strategy.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Yes, MinMax doesn’t meet the luxury cosmetic
look-good criteria that RP meets. </div>
<div dir="auto"><br>
</div>
<div dir="auto">But for one thing, I remind you that natural (
sincere) top-cycles are vanishingly-rare.</div>
<div dir="auto"><br>
</div>
<div dir="auto">So do you want to have less strategy-protection,
in order for the result to maybe look better in a vanishingly
rare natural top/cycle?</div>
<div dir="auto"><br>
</div>
<div dir="auto">…& how bad is a violation of Condorcet-Loser
anyway. “Beaten by all the other alternatives” sounds like some
kind of unanimity, but of course it isn’t. It isn’t like a
Pareto-violation. I remind you that the MinMax winner has fewer
voters preferring some particular candidate over him than anyone
else does.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Clone-Criterion violation? How bad that really in
MinMax, especially when we’re talking about a vanishingly rare
natural top-cycle?</div>
<div dir="auto"><br>
</div>
<div dir="auto">RP(margins) for a completely honest electorate.</div>
<div dir="auto"><br>
</div>
<div dir="auto">MinMax(wv) for public elections.</div>
<div dir="auto"><br>
</div>
<div dir="auto">..& about a primary to reduce the candidates
to 5: Forget the primary. If you think people will have trouble
rank-ordering lots of candidates, I remind you that, to vote
among them in a primary, they’d still have to examine &
choose among the initial many candidates.</div>
<div dir="auto"><br>
</div>
<div dir="auto">…harder than ranking only the ones you know &
regard as deserving & definitely in your accepts&
preferred set.</div>
<div dir="auto"><br>
<div class="gmail_quote" dir="auto">
<div dir="ltr" class="gmail_attr">On Wed, Sep 13, 2023 at
00:18 Colin Champion <<a
href="mailto:colin.champion@routemaster.app"
moz-do-not-send="true">colin.champion@routemaster.app</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)">I
notice that RP is the only election method mentioned by name
in the <br>
Virginia agenda.<br>
<br>
A while ago I ran some simulations on elections with
truncated ballots. <br>
Something I noticed was that the presence of RP in the list
of methods <br>
made the software unacceptably slow. I didn't look into the
cause, but <br>
there's a natural explanation, which is the fact that RP is
known to be <br>
NP-complete when it deals correctly with tied margins, i.e.
by <br>
exhausting over all their permutations. Presumably if some
candidates <br>
are unpopular and ballots are extensively truncated, then
tied margins <br>
are much likelier than with complete ballots.<br>
<br>
I gather that practical implementations of RP choose a
random <br>
permutation rather than exhausting. This seems to me to
bring a danger. <br>
The presence of a few vanity candidates (truncated off
almost all <br>
ballots) may lead to ties, and this may lead to a
comfortable winner <br>
looking as though he owes his victory to a coin-toss.
Obviously this <br>
undermines the legitimacy of his win.<br>
<br>
CJC<br>
----<br>
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</blockquote>
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