[EM] Let's play Jenga!

[Ross Hyman]

Hi Kristofer,I found Warren Smith's votedesc.pdf document on M. Schulze's site: http://m-schulze.9mail.de/votedesc.pdf 
This is a great document.  I think it should be on the Election Methods website, especially since most of the other links to election method descriptions are broken. 

The variation I am proposing to Warren's Maxtree method is to constrain the form of the spanning tree to a directed chain (or whatever the official name is) A>B>C>D....  and then maximize the minimum link.  I haven't had time to think about it too much but I am hoping the method will satisfy local independence of irrelevant alternatives.  

What's up with the election methods list?  I have not seen my posting or your response to it on the archive, which is what I read.  I don't get the emails.  The last posting in the archive is from Sept 28.  

Best,Ross














    On Sunday, October 1, 2017 2:02 PM, Kristofer Munsterhjelm <km_elmet at t-online.de> wrote:
 

 On 10/01/2017 02:42 PM, Ross Hyman wrote:
> Repeatedly remove the weakest link whose removal leaves at least one
> ranking of all of the candidates in which there is a direct win for the
> higher candidate over the next lower candidate.  When only one such
> ranking exists, elect that ranking of candidates.
>
> This method is different from Tideman Ranked pairs.
> Consider the pair ordering B>D, B>A, C>B, D>C, C>A, A>D.
> The above method produces: D>C>B>A. The Tideman order is C>B>A>D.  The
> Tideman order is better. The Schulze winner is also C.

Warren's Maxtree method is another Ranked-Pairs-like that it might be 
interesting to investigate. The method's logic is akin to:

- Ranked Pairs is similar to Kruskal's algorithm for finding a minimum 
spanning tree in an undirected graph.
- But the graph induced by the Condorcet matrix is directed.
- So use an MST algorithm for weighted graphs instead.
- This algorithm is Chu-Liu-Edmonds and the method becomes max-tree. 
(See Warren's votedesc.pdf for more information)

I've never got around to implementing it, though.


   
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20171007/3e6e7e79/attachment-0001.html>