[EM] Schulze definition (was: information content, game theory, cooperation)

Juho Laatu juho4880 at yahoo.co.uk
Sun Jun 7 14:20:20 PDT 2009


To me all this sounds still a bit too
complex for the referendum. I'd drop
out all the criteria, Smith set etc.
since the voters will not understand.

There is also the risk that experts
and opponents of the reform will
"sabotage" the referendum by digging
into the details (and thereby
"proving" to the voters that the
method is too complex).

The question in the referendum can
not in any case define the complete
method. It may be enough to make it
clear in the question that the method
is a ranked method (the voters may
understand even have interest in this
point) and that it is a Condorcet
method (if you want to rule out e.g.
IRV). If the question clearly points
out the group of Condorcet methods
and it will be approved, then it may
be natural to pick the Schulze method
since it is anyway the most used
Condorcet method.

It could be thus enough to say:
- The electors rank the candidates
  according to their preferences.
- If some candidate is preferred over
  all other candidates then that
  candidate shall be elected.

Juho


--- On Sun, 7/6/09, Raph Frank <raphfrk at gmail.com> wrote:

> On Sun, Jun
> 7, 2009 at 7:35 PM, Árpád Magosányi <magwas at rabic.org>
> wrote:
> 
> """"
> 
> - The electors rank the candidates according to their
> preferences.
> 
> - If there is a group of candidates all preferred over all
> candidates
> outside the group, then ignoring the candidates outside the
> group should
> not change the outcome of the election.
> 
> - The winner should be choosen from the above group in a
> way that guarantees that if a candidate
> similar to an already running candidate is introduced, the
> outcome of
> the election is not changed, and the less controversial
> candidates are preferred.
> """
> Reasoning below. Please point out possible mistakes and
> ways to better phrase it between the boundary conditions
> given (simple words, no expert terms like
> "Schulze" or "beatpath", and should be
> matchable to correct mathematical definitions.
> 
> 
> Ok, so you are basically saying (in simple terms)
> 
> A) the method is a ranked method
> B) All candidates outside the Smith set can be ignored
> without changing the result
> C) The method should be clone independent.
> 
> 
> That is a pretty good idea.  You are in effect defining
> the characteristics that Schulze meets and the others
> don't.
> 
> Wikipedia has a table at:
> 
> http://en.wikipedia.org/wiki/Schulze_method
> 
> 
> Schulze and ranked pairs are the only methods that meet
> clone independence and the condorcet rule.
> 
> Does ranked pairs fail the Smith criterion?
> 
> I would change B to "If there is a group of candidates
> all preferred over all candidates
> outside the group, then only those candidates may win and
> the candidates outside the group may have no effect on the
> result".
> 
> If you don't restrict the winner to the Smith set
> (which your rules don't necessarily), then you could end
> up with a non-condorcet method.
> 
> 
> Also, just because the popular/proposed condorcet methods
> are excluded by your definition doesn't mean that some
> other weird method can't be found that also meets the
> rule.
> 
> It might be better to just include the reasons that you
> like Sculze and use those rules rather than trying to select
> Sculze by a process of elimination.
> 
> 
> 
> BTW it would be nice if the wikipedia page would actually
> contain something describing Schulze method, not just the
> heuristics.
> 
> 
> The best I have found so far is:
> http://rangevoting.org/SchulzeExplan.html
> "Therefore, my aim was to find a method that satisfies
> Condorcet,
> monotonicity, clone-immunity, majority for solid
> coalitions,
> and reversal symmetry, and that tends to produce
> winners with weak worst
> pairwise defeats (compared to the worst pairwise defeat of
> the winner
> of Tideman's Ranked Pairs
> method)."
> 
> Yeah.  Though, ofc, Schulze isn't allow to edit the
> article.
> 
> Could someone on this list give a brief outline or the
> formal rule (actually his statutory rules are probably it)?
> 
> 
> 
> 
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> 
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