Purely as a FYI on Schulze method, it is implemented in the Liquid Feedback system: http://liquidfeedback.org/
Liquid Feedback has been used for years in Central Europe, notably by several chapters of the Pirate Party, but also some cooperatives, etc. Note: LF itself is IMO not suitable for use by SPI - at least not within the scope of the proposal now discussed. Note: My intent here is to be purely informational. I'm not advocating for or against the Schulze method compared to other STV methods. henrik On Sat, Mar 4, 2017 at 3:01 PM, Markus Schulze <markus.schu...@alumni.tu-berlin.de> wrote: > Hallo, > > I recommend Schulze STV. This method is described mainly > in section 9 of this paper: > > http://m-schulze.9mail.de/verylong.pdf > > Source codes can be found here: > > http://m-schulze.9mail.de/schulze3.zip > > multi01g.cpp is multi-threading for g++. > multi01v.cpp is multi-threading for Microsoft Visual C++. > singl01g.cpp is single-threading for g++. > singl01v.cpp is single-threading for Microsoft Visual C++. > > ********* > > When Schulze STV is used, then each voter gets a complete > list of all candidates and ranks these candidates in order > of preference. The individual voter may give the same > preference to more than one candidate and he may keep > candidates unranked. > > ********* > > Schulze STV is an STV method, in so far as it satisfies > Dummett-Droop Proportionality: When strictly more than > x Droop Quotas of voters strictly prefer every candidate > of a set B of (at least x) candidates, then at least > x candidates of set B must be elected. (See section 9.3 > of "verylong.pdf".) > > ********* > > In single-winner elections, a "Condorcet winner" is a > candidate who wins every 2-way contest. The property of > being a Condorcet winner is very important because, when > some candidate X is a Condorcet winner, then candidate X > is also a Condorcet winner when some other candidate is > removed. So when some candidate X is a Condorcet winner, > we can declare this candidate the winner, knowing that > he doesn't owe his win to the presence of some other > candidate. > > Schulze STV has the following property: Suppose M is the > number of seats. When some candidate X wins in every > (M+1)-candidate contest, then he is also a winner overall. > Again, the property of winning in every (M+1)-candidate > contest is important because, when some candidate X has > this property, then candidate X still has this property > when some other candidate is removed. (See section 9.4 > of "verylong.pdf".) > > ********* > > The analysis of Schulze STV is very short because most > of its properties follow directly from the fact that, > in the single-winner case, Schulze STV is identical to > the Schulze single-winner election method, which is > analyzed in sections 2--4 of "verylong.pdf". The Schulze > single-winner election method is currently used by SPI. > > Markus Schulze > > > _______________________________________________ > Spi-general mailing list > Spi-general@lists.spi-inc.org > http://lists.spi-inc.org/listinfo/spi-general -- henrik.i...@avoinelama.fi +358-40-5697354 skype: henrik.ingo irc: hingo www.openlife.cc My LinkedIn profile: http://fi.linkedin.com/pub/henrik-ingo/3/232/8a7 _______________________________________________ Spi-general mailing list Spi-general@lists.spi-inc.org http://lists.spi-inc.org/listinfo/spi-general
