[EM] smith/schwartz/landau

[Curt]

> On Mar 23, 2018, at 6:36 PM, robert bristow-johnson <rbj at audioimagination.com> wrote:
> ---------------------------- Original Message ----------------------------
> From: "Curt" <accounts at museworld.com>
> --------------------------------------------------------------------------
> > https://github.com/tunesmith/condorcet-counter <https://github.com/tunesmith/condorcet-counter>
> >
> > I opined a bit in the README but that’s not really the point of the project. I just wanted an easy way to identify Smith and Schwartz sets for myself.
>  
> 
> to wit: "It's this author's view that a method should only be called a Condorcet if it is limited to identifying the Smith Set,"
> 
> seems to me that your view is that the current definition of "Condorcet-compliant-method" should be changed.  so is Tideman Ranked-Pairs or Schulze Beat-Path methods not "Condorcet methods"?
> 

Yes, that is my view. They should not be called “Condorcet Methods”, because they are not guaranteed to select the candidate(s) that would defeat all other candidates.

There is a clear difference between a “Condorcet Method” that finds a Condorcet Winner or Smith Set, and a “tiebreaking" method that tries to pick a single winner from a multi-candidate Smith Set. The latter fails criteria that the former does not. I don’t know what we should call these tiebreaking algorithms - perhaps they are not quite “tiebreaking” methods since a cycle is not exactly a tie. But it isn’t appropriate to call them “Completion” methods either as that implies something that it isn’t.

The actual objection I have is that when both are described as “Condorcet Methods”, then it’s too easy in the literature (and the blogs, and the wikipedia articles, particularly from Condorcet detractors) to paint with a broad brush and argue that all Condorcet Methods are flawed in some manner, same as how all other methods are “unfair” in some way, which ultimately does a disservice to the Condorcet Method. An election that has a Condorcet Winner is not unfair in those ways, compared to something like IRV or Plurality or Top-Two.

It might worth a survey of what a Smith Set actually *means*. I believe it signifies something valuable about the electorate, beyond just an indication that the election is “incomplete” and that we should apply some algorithm to divine a single winner from it.

(Regarding the typo in my README - I meant “should only be called a Condorcet *Method* if it is…”)

Curt

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