# [EM] MMPO

Michael Ossipoff email9648742 at gmail.com
Sat Oct 1 15:16:09 PDT 2016

```Yes, avoiding the Plurality criticism could be worth requiring 1/8 of the A
voters to truncate B.

There could be an agreement between A & B voters, to rank eachother's
candidate with 7/8 probability.

"Flip a coin 4 times. If it comes down the same way every time, then don't
rank them."

That reminds me of the Srategic-Fractional-Support anti-defection
strategy-suggestion that you made some time ago, & which I've been
advocating.

It's for methods without built-in chicken-dilemma protection, such as
Approval.

In one version, faction A could try to probabilistically give  faction B
just enough votes to make B win if the B faction is bigger than the A
faction believes itself to be.

Sure, it's a guess, but the A faction's guess is as good as the B faction's
guess. They both have access to the same predictive information.

So the fact that the  A faction is trying that should deter defection by
the B faction.

It, too, could be done probabilistically, but it's one reason why I like 0
to 99 or 0 to 999 Score voting.

Also, in Approval, amicable factions could probabilistically give
eachother's candidate some near-unity fraction of an approval. They're
effectively fully helping eachother, but the bigger faction will
automatically outpoll the other.

Michael Ossipoff

On Oct 1, 2016 12:09 PM, "Forest Simmons" <fsimmons at pcc.edu> wrote:
>
> Here's an idea for fixing MMPO's lack of  Plurality compliabnce:
>
> Include the opposition of the Implicit Approval Cutoff Candidate, the
virtual candidate on the truncation boundary.
>
> Example:
>
> 40 A
> 10 C>A
> 10 C>B
> 40 B
>
> In regular MMPO, the max opposition to C is 40.  But when the number of
ballots on which C is truncated is counted among the oppositions, the max
opposition becomes 80.  Thus Plurality is rescued.
>
> How about the Chicken problem?
>
> Consider
>
> 49 C
> 3 A  (sincere A>B)
> 24 A>B
> 24 B (sincere B>A)
>
> Regular MMPO gives A the win contrary to Plurality.
> Taking the truncation opposition into account we have max oppositions for
A, B, and C, respectively, as  73, 52, and 51.  Candidate C wins, punishing
B's defection.  This only required three of the A supporters to truncate B.
>
> Unfortunately, even this new version of MMPO fails Condorcet Loser and
Clone Winner.
>
> ----
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>
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