[EM] New Criterion: The Co-operation/Defection Criterion

[Kevin Venzke]

Hi Mike,

--- En date de : Lun 24.10.11, MIKE OSSIPOFF <nkklrp at hotmail.com> a écrit :
> You wrote:
>  
>  Basically A will have a majority over B
>  
> endquote
>  
> Not necessarily. A will certainly have a pairwise win over
> B. When the non {A,B} 
> candidates lose, and MMPO is applied to its A,B tie, that
> pairwise win will mean
> that B has a greater pairwise opposition than A does.

Thanks for the correction.

So, when I reduce this to pairwise terms (which I do for convenience)
I see this criterion in effect:

If some candidate A has simple pairwise wins over every candidate in
a set of candidates "B" and has no majority pairwise losses to any
candidate in a set of candidates "C", and every candidate in the set
"C" has a majority pairwise loss to every candidate in set "B," then
candidate A must win.

If it wasn't already clear, this definitely won't be compatible with
the Plurality criterion. I know that won't bother you though.

As far as methods that will satisfy it, we at least have some clumsy 
ones. Any Condorcet method used to complete majority-defeat-
disqualification or CDTT (i.e. Schwartz set that replaces sub-majority
wins with ties) will do the trick. These methods would also satisfy
SDSC fully.

I am not sure that MMPO as you propose it actually does the trick.
It seems to depend on the A-B tied score which I'm not sure is 
guaranteed. Particularly if "C" is multiple candidates.

Kevin