[EM] Condorcet Criterion for plurality.

[Markus Schulze]

Dear participants,

it is clear why Mike Ossipoff is unwilling to understand that
plurality can be defined on preferential ballots: He wants to be
able to claim that plurality meets the Independence from Irrelevant
Alternatives Criterion (IIAC). He wants to be able to claim that
even plurality was better than IRV.

Mike Ossipoff wrote (10 Nov 2000):
> There are certainly a number of ways in which Plurality is better
> than IRV: Participation, IIAC, Consistency, etc.

Mike Ossipoff wrote to Blake Cretney (13 Nov 2000):
> Here's what I think is meant by IIAC: Deleting a loser from the
> ballots, and then recounting those ballots, should never change who
> wins. It _is_ meaningful to say that Approval & Plurality meet this
> simple criterion.

Mike Ossipoff wrote to Blake Cretney (14 Nov 2000):
> It isn't at all clear why you think that it's meaningless that
> Approval and Plurality pass IIAC. On the contrary, it's very relevant,
> because IRVies, as I said, always bring up Arrow. IIAC isn't one of
> the criteria important to me, but it's quite relevant because Arrow
> is brought up so often. You seem to be saying that the relevance of
> a method passing IIAC depends on whether that method is a rank method,
> and it isn't at all clear why you believe that. Criteria are written
> because someone is saying that they're desirable to comply with. If
> a method complies, it complies, regardless of its balloting or other
> procedural details.

Markus Schulze