[Election-Methods] Condorcet methods differ greatly in burial resistance

[Kevin Venzke]

Warren,

--- Warren Smith <wds at math.temple.edu> a écrit :
>Our results greatly-contradict the usual previous thinking that the 
>differences between Condorcet methods in vulnerability to strategy, are 
>small. That's interesting and new. 

>So maybe the internet Condorcet community should now re-evaluate which 
>Condorcet variants they prefer. (As well as re-evaluate how well they 
>claim to have "understood" Condorcet strategy. It appears they were 
>overconfident in their assertions of understanding.) 

Those of the "internet Condorcet community," who have taken an interest in
comparing Condorcet methods' burial resistance, typically don't restrict
themselves to the assumption that truncation is not allowed or not a
strategy. Thus I don't know whose views you are attacking here. I am more
surprised to hear the apparent claim that there may be a Condorcet method
that disallows truncation and which is not a total disaster due to burial.


Here is Warren's main finding:

>THEOREM (BLACK BURIAL-RESISTANCE): In N-candidate elections (N≥3
fixed) 
>in the random elections model, using pure-rank-orderings as votes, 
>consider the "burial" strategy where everybody who voted X=top C=second, 
>now artificially votes C=bottom (but aside from that, all votes 
>unchanged). Here C denotes the Black-winner with honest votes. Then: with 
>probability→100% in the #voters→∞ limit, the new winner
will be neither 
>C nor X. And when it is not X, that means burial "does not work." 

Kevin Venzke


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