[EM] "Strategies"

[Kevin Venzke]

 --- josh at narins.net a écrit : > 
> Is there a single ranked ballot system that is not subject to favorite
> burying?
> 
> What systems, other than fptp, are immune, if any?

This is another way of asking what systems meet Weak FBC, right?

FPTP isn't immune.  (Not sure if you implied that it is.)

Approval is immune if you define "favorite" as your first-place choice,
and it's okay to rank candidates equal to favorite.  Approval variants
like MCA and MinMax(pairwise opposition) should be immune, too.

"Conditional Approval" (if you'll indulge me) isn't immune because of cases
like the following.  The first bloc of voters causes C to win by ranking
A first.  If they had just voted B in first, B would've won.
35 AB >  > C  (A is the true favorite.)
25 AC >  > B
16 B > C > A
24 C > A > B
(Resolution: A leads with 60 votes to B's 51 and C's 49.  In response,
C obtains 16 more votes for a total of 65.  No one obtains votes in response
to this, so C wins, having taken the lead.)

I think Condorcet may be immune if you use Approval to break cycles, but
I'm not positive.  There might be incentive to create or prevent a cycle.

Random Ballot is immune.  And I think that's it.

Kevin Venzke
stepjak at yahoo.fr


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