3-valued Booleans inside rules, passing Condorcet (Re: [EM] "More often" (was: IRV and Condorcet operating identically)

Dave Ketchum davek at clarityconnect.com
Sat Mar 1 23:38:37 PST 2003


On Sun, 02 Mar 2003 09:58:47 +1300 Craig Carey wrote in part:

> At 03\03\01 09:49 -0500 Saturday, Stephane Rouillon wrote:
> ...
>  >what is the participation criterion?
>  >
>  >Steph
>  >
>  >Markus Schulze a écrit :
>  >
>  >> > FBC is the only criteria that favors Approval
>  >> > over Condorcet.
>  >>
>  >> Condorcet violates the participation criterion.
>  >> Approval Voting meets the participation criterion.
>  >>
> 
> And the missing third sentence is: both statements are so
> unimportant as to be best ignored.
> 
> There is no clue there on the weightiness of the claims. I am
> sure that they are not important. Certainly that view can locked
> down if the definition of the "criterion" is not available.
> 
> To the extent possible, please regard the following comments being
> about an election having only the papers (AB), (B), and (C). For
> that election, the Condorcet method has an undefined region of
> quite a big size.


Seems like "undefined region" is an unfortunate label.  Agreed that 
Condorcet has cycles, and that its basic definition allows these to exist 
but does not provide a resolution for them.

STILL, this problem is recognized and I do not hear anyone being dumb 
enough to propose actual use of Condorcet without completing the 
definition of the method by specifying how to process cycles (while it is 
true that there is debate as to exactly what to do with them).

For a method to be complete and ready for actual use in elections it MUST 
specify response for every possible collection of ballots (papers).

IRV also has an undefined region, while smaller - what to do when two weak 
candidates are equal, and thus neither can be discarded as weakest.

> 
> It is controversial to create a weak rule and see that it passes
> some methods and not others. Instead a plausible rule that fails
> all the methods that need to pass can be used, but it is length
> (or bigness) of the worst failure is measured. It looked
> interesting when 2 winner 4 candidate STV was proven at the STV
> mailing list to be not monotonic with the support rise harmed
> being about 17%.
> ______________
> 
> G. A. Craig Carey

-- 
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   Dave Ketchum    108 Halstead Ave, Owego, NY  13827-1708    607-687-5026
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