[EM] Ultimate SPE Agenda Processing: Sink Swap Bubble

[Forest Simmons]

Here's a compromise:

Let A be the Agenda Uncovering winner.

If voters are sincere, A is my best estimate of who should be elected.

If A is defeated pairwise, then the votes are probably not sincere.

So if A is undefeated, elect A ... Else elect C, the Most Favorable Enemy
of A ... the candidate most likely to have been thrown under the bus by the
A voters to create an artificial cycle to their advantage.

If a sufficient number challenges the outcome, have a manual runoff between
A and C.

This won't punish A, but it will make the burial futile ... a big waste of
time ... putting some friction into the dynamics.

-Forest

On Wed, Apr 5, 2023, 2:28 AM Kristofer Munsterhjelm <km_elmet at t-online.de>
wrote:

> On 4/4/23 07:23, Forest Simmons wrote:
> >
> >
> > On Mon, Apr 3, 2023, 2:20 AM Kristofer Munsterhjelm
> > <km_elmet at t-online.de <mailto:km_elmet at t-online.de>> wrote:
>
> >> This is about chicken resistance in general, no? I suspect there's
> >> a more general impossibility result hiding here: that methods that
> >> are burial resistant and Condorcet (in the way the Smith-IRV
> >> hybrids or Friendly is) have to make uncharitable interpretations
> >> of ballots that, if they were honest, would imply a very different
> >> candidate should be elected. (I have no proof of this, but it seems
> >> a reasonable hunch.)
> > This is exactly what I have found. Classical Condorcet assumes honest,
> > sincere voters with imperfect estimation of the truth ... wv majorities
> > have the best chance of discerning that truth. But, as examples show ...
> > these methods are easily subverted by unscrupulous opportunistic
> > sophisticated voyers.... and as you and Kevin have noted, methods that
> > punish burial and defection must sacrifice VSE ... until the
> > unscrupulous learn it will almost always back fire.  When everybody
> > learns that lesson, the sincere CW will be a ballot CW much more
> frequently.
>
> Perhaps there is some kind of pigeonhole argument that could prove it,
> but yes, it makes sense. Intuitively there's a Pareto front where, every
> type of strategy resistance level, there's an optimal VSE method, and
> that this optimum value shrinks the more strategy-resistant the method
> is... because a constrained optimum is never *better* than an
> unconstrained one. Of course, this informal argument does not show how
> "expensive" strategy resistance is, only that we shouldn't be surprised
> if there's some cost.
>
> (Although the general argument could also be used to shown that
> cloneproof methods, say, can't be any better VSE-wise than the best VSE
> method without a constraint of cloneproofness, in that case it seems
> that the price is much lower. Anyway.)
>
> >> And then the ultimate deluxe method (in one sense) would be
> >> something along the lines of:
> >>
> >> - Conduct an election with "honest" method X and "suspicious method" Y
> >> (or putting it differently, "compromise resistant" X and "burial
> >> resistant" Y).
> >> - If the winners are equal, we're done.
> >> - Otherwise do a manual runoff, where the voters' behavior will be
> >> honest (majority rule with two candidates is incentive compatible).
> >> Elect the winner.
> >
> >
> > That's easier said than done ... definitely needs more explorstion.
>
> > But hears the subtle difficulty of a combo method:
> >
> > Suppose C is the sincere CW and A creates a cycle by burial of C under
> > the bus B. The honest methods, including wv, SPE, Agenda Uncovering,
> > etc. ... all choose A. The burial resistant methods all choose the bus B.
> >
> > A sincere runoff between A and B will choose A.
> >
> > On the other hand, the sincerity checks of Bubba and Agenda Chain
> > Climbing will restore C.
> >
> > But restoring C makes burial less risky for the buriers!
>
> That's a good point. But we should be careful not to take this too far.
> Suppose that we have a set of elections, e_1...e_n, and a subset of
> these, call it ebA, where burial is advantageous in method A. Then
> suppose ebB is a strict subset of ebA and denotes the elections where
> burial is advantageous in method B.
>
> Then all else equal, we would consider B to be a better method than A,
> even though B seems to make burial less risky for buriers.
>
> What we need to consider is under what elections are there nearby
> elections where burying X doesn't make Y win, but makes Z win instead.
> That's where burial backfires. Now if these are reduced, then you could
> say that it's ambiguous whether the new method is better, because the
> rate of burial would increase. But we don't know that this is the case
> for the (A vs C) runoff overlay.
>
> Or putting it differently: random ballot has no risk whatsoever for
> burial... but no reward either, so it's okay.
>
> I agree, it doees make the method much harder to analyze, though.
> Perhaps I'll try to find an optimal runoff-based method using my optimal
> strategy susceptibility analysis at some point and see what the rate is :-)
>
> James Green-Armytage considered a different way to break UD: by having
> allies of the honest CW be able to withdraw from the election.
> https://jamesgreenarmytage.com/dodgson.pdf I haven't read the paper, but
> from the abstract it seems he's saying that in 1D space, the resulting
> method is strategy-proof (!)
>
> -km
>
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