[EM] Voting Benchmark

Markus Schulze markus.schulze at alumni.tu-berlin.de
Thu Oct 1 13:14:25 PDT 2015


Hallo,

 > Thank you for the reply. So it seems pretty essential
 > to get these nice properties. I wonder if there are
 > other ways to get them, i.e. it's not proven to be
 > the only way to get these properties I guess?

Well, you could calculate the Schwartz set and then
eliminate all those candidates who are not in the
Schwartz set and then apply the Schulze method with
"pairwise opposition" to the remaining candidates.
But this would violate monotonicity because it could
happen that, by ranking the candidate A higher, some
other candidate B, who was in the strongest path from
candidate A to some other candidate C, is kicked out
of the Schwartz set.

You could use the Schulze method with "pairwise
opposition" to calculate a complete ranking of all
candidates and then declare the highest ranked
candidate elected who is in the Schwartz set.
This would satisfy monotonicity, but violate
independence of Smith-dominated alternatives.

Markus Schulze



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