[EM] Meta-criteria 6 of 9: Heuristics. #1, simplicity

[Kristofer Munsterhjelm]

Juho wrote:

> One could discuss which rule should apply in those special cases when 
> both criteria can not be met. In order to determine exactly when we have 
> true clones in our hands we would need to have the original votes, and 
> also the preference strengths to know if the candidates are closely 
> related or not. (Actually also near clones should be treated as clones 
> since we can not expect that all voters treat those candidates as 
> clones.) The pairwise matrix contains only partial information. If we 
> make a method 100% clone proof using the matrix information only we can 
> not limit to the clone cases only but we are bound to influence the 
> result also in other cases. One pairwise matrix can be obtained both 
> from votes that have clones and from votes that do not have clones. It 
> is for example possible that no voter ranks together those candidates 
> that we must now deem to be (potential) clones since there is a 
> possibility that in some other vote set they could be clones. The 
> Schulze method uses path heuristics to eliminate all cases where clones 
> could exist and influence the end result.
> 
> (Are there other strong reasons behind the use of paths? In real life 
> the existence of the long beat paths maybe doesn't refer to any natural 
> key target.)

Schulze's primary argument is that the use of paths let one make a 
method that is very close to Minmax, yet is cloneproof and elects from 
Smith. Thus, if one thinks the Minmax yardstick is a good one, yet that 
Minmax's clone susceptibility means one has to diverge from it in 
certain cases, Schulze is a good method.

As for your second part, there is naturally a tradeoff between strong 
paths and short paths. Schulze considers paths equally no matter their 
length, but the question is sensible. Methods that focus on short paths 
are more like Copeland (which focuses on "paths" of a single step), and 
methods that elect from the uncovered set would have short paths from 
the winners to the candidates not in the uncovered set.