[EM] eliminations methods like IRV

[Bart Ingles]

Bart Ingles wrote:
> 
> Forest Simmons wrote:
> >
> > 40 BUVWCXYZA
> > 25 UVWCABXYZ
> > 35 AUVWBXYZC
> >
> > In this version (Blake's example with steroids) nobody can deny that some
> > of the candidates are much better than others, for example U is strongly
> > preferred over Z by all the voters.
> 
> Not necessarily; suppose ratings or utilities are considered:
> 
>      1.0              0.5               0.0
>      --------------------------------------
> 40   B                             UVWCXYZA
> 25   UVWCABXY                             Z
> 35   A                             UVWBXYZC
> 
> We can safely infer from the rankings that U is strongly preferred over
> A by the middle group, at least as strongly as that group prefers anyone
> over anyone, only because U and A contain both the first and last
> choice.  For the two larger groups it's not possible to make that
> inference.

Whoops, I meant U and Z.