[EM] Re: MDD,ER-Bucklin (whole)
Chris Benham
chrisbenham at bigpond.com
Fri Oct 21 08:23:25 PDT 2005
Kevin,
You are right, I erred. MDD,ER-Bucklin(Whole) doesn't meet
Smith(Gross), so scrub that and replace
it with "Condorcet(Gross)".
Douglas Woodall gives this demonstration:
49: a>b>c>d>i>j>k>e>f>g>h
31: e>f>g>h>j>k>i>a>b>c>d
20: k>i>j>a>b>c>d>e>f>g>h
>The Smith set is {i,j,k} (beating a,b,c,d by 51 to 49 and e,f,g,h by
>69 to 31). But i beats j by 69 to 31, j beats k by 80 to 20, and k
>beats i by 51 to 49, so that every candidate has a majority-strength
>defeat. Thus the MDD bit has no effect, and the method reduces to
>Bucklin. No candidate has a majority in the top three preferences,
>and if the top four preferences are counted then A wins. But A is
>not in the Smith set.
>
I don't consider this to be a serious drawback, and I don't doubt
that you are right that compliance
with any sort of top-cycle criterion is incompatible with FBC.
Chris Benham
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