[EM] proportional constraints - help needed

[Kristofer Munsterhjelm]

On 02/12/2013 12:24 AM, Jameson Quinn wrote:
>
> What does monotone even mean for PR? You can make something that's
> sequentially monotone, but it's (I think) impossible to avoid situations
> where AB were winning but changing C>A>B to A>B>C causes B to lose (or
> variants of this kind of problem). That's still technically "monotone",
> but from a voters perspective, it's not usefully so.

I was thinking of a one-candidate generalization to monotonicity, yes. 
That is, say that X is on the council. Then if some voters raise X on 
their ballots, that should not kick X off the council.

But wouldn't this imply the more strict monotonicity you're talking 
about? Say A and B are in the council. Then you raise B, changing C>A>B 
into C>B>A and then into B>C>A. By monotonicity, B shouldn't stop 
winning. Now you raise A by changing B>C>A into B>A>C and finally into 
A>B>C. Again, by monotonicity, A shouldn't stop winning.

I think I've described the method in an earlier post. (Incidentally, 
it's Bucklin-based.) I could also provide source code if you want to 
test it on a situation or impossibility proof that Droop proportionality 
is incompatible with monotonicity. It could use the review :-)