[EM] Not satisfied with AOCBucklin's defection-resistance.

[Michael Ossipoff]

With AOCBucklin, in the usual Approval bad-example, with candidates A, B, and C:

It would be the advantage of the C voters to throw an apple of discord
among the {A,B} voters, by giving a conditional vote to B. The C
voters would have nothing to lose thereby.

Then, if the A voters gave a conditional vote to B, B could give one
to A and to C, and the result would be to acquire a vote-total 3 times
the size of their faction. Letting the letters stand for the number of
people in the factions: A would have A + B votes. B would have 3B
votes. C would have C + B votes.  Plainly, there's a wide range of
faction-size configurations in which B would win.

So, that giving, by the C voters, of a conditional vote to B would
cause a chicken dilemma for the A voters and the B voters. That was
what I was referring to before, when I mentioned a 2nd-order chicken
dilemma.

True, it wouldn't be naturally-occurring. It would need the C voters
to set it up. But they'd have no reason not to. And sometimes it would
benefit them, when the both the A and B voters defected.
The B voters would defect by giving a conditional vote to C. The A
voters would defect by not giving one to B, in order to deter their
defection, or at least not reward it.

So I have to reluctantly withdraw my proposal of AOCBucklin.

ICT and TERW have better defection-resistance, and usually, if not
always, pass MMC. i don't like an occasional chance MMC-failure to
throw the win out of the majority-preferred set, but without good
defection-resistance, it isn't really possible (for AOCBucklin) to
fullly benefit from MMC anyway.

In official public elections in this country, Beatpath, etc. can't
benefit from its compliance with the Condorcet Criterion, MMC, and
Condorcet Loser, because of its failure of FBC and CD.

Anyway, because benefit from MMC depends on FBC and CD, that's why it
would be so desirable to meet FBC, CD, with good defection-resistance,
and MMC.

Can that be done?

Mike Ossipoff