[EM] New Condorcet/RP variant

Steve Eppley seppley at alumni.caltech.edu
Fri Nov 5 12:47:40 PST 2004


Markus S wrote:
> Steve E wrote (5 Nov 2004):
>> If he thinks it matters, hopefully Markus will tell us
>> which MTM tiebreaker he has in mind.
> Your "minimize thwarted majorities" (MTM) method has been
> defined here (23 Feb 2000):
> http://lists.electorama.com/htdig.cgi/election-methods-electorama.com/2000-February/003600.html
>    Minimize Thwarted Majorities (MTM)
>    ----------------------------------
>    If Vij > Vji and the social ordering ranks j ahead of i,
>    then the social ordering "thwarts" the Vij majority who
>    ranked i ahead of j.
>    Select as the social ordering the ordering which
>    minimizes thwarted majorities.
>    By "minimizing" thwarted majorities, I mean that to compare 
>    two orderings to see which is better, we compare each
>    ordering's largest thwarted majority.  If that's a tie
>    then compare their second largest, etc.

Ah.  Thanks for the clarification.  That definition was 
both old and abbreviated.  The method evolved into MAM.

If no pairing is a tie and no two pairings have the same
size majority, that old definition produces the same 
social ordering that MAM does.  So it may still be a 
useful description in the context of elections having 
many voters.


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