[EM] Condorcet cyclic drop rule
nkklrp at hotmail.com
Wed Apr 4 20:18:32 PDT 2001
>Here's another issue, then. At one time, people on this list used the
>term "Condorcet's method" to mean choosing the candidate whose
>greatest defeat was least (Minmax). Of course, based on the confusion
>we have recently been discussing, this was defined using
>"defeat-support" instead of margins. My impression is that it was you
>who claimed that this method is what Condorcet intended, but I might
It was I & Norm. Norm pretty much settled the issue in favor of
defeat-support, as what Condorcet's wording meant.
>At one time, I suspected that you had taken Condorcet's words out of
>context. That he had said, take the candidate whose greatest defeat
>is least, when referring to a three candidate example, and you had
>extrapolated it to all examples. I have read a great deal of
>Condorcet, and I can't find even this kind of statement. Can you give
>me the quote on which the minmax interpretation was based? This
>question is open to anyone, not just Mike.
It's based on the Condorcet translation that you posted on the
same day that you posted this message that I'm replying to.
Electing the candidate whose greatest defeat is the least is the
same as dropping the weakest defeat, and repeating that till someone
is unbeaten. I worded it in the "minmax" way because that seemed
briefer & simpler at that time. Now I realize that Condorcet's
approach is much more compelling in terms of motivation. But yes,
my "minmax" wording wasn't used by Condorcet. However it's been
widely used by various journal authors, referring to it as Condorcet's
method. For instance, it seems to me that Condorcet's method is
defined that way in Fishburn's well-known survey article--probably
in the '70s.
>I note that Rob Lanphier still uses "Condorcet's method" with the
Yes, since that's an equivalent way of saying the definition that's
the literal interpretation of Condorcet's own wording of his
drop-weakest definition, the one that you quoted the translation of
in your message posted the same day as this message to which I'm now
Relatively recently we've found out about Tidmean's Ranked Pairs
interpretation of Condorcet's top-down proposal, and about SSD,
which is another possible interpretation (but not the literal
interpretation) of Condorcet's bottom-up definition.
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