[EM] Thorough Expeditious Elimination

[Kristofer Munsterhjelm]

On 3/21/23 04:40, Forest Simmons wrote:

> So, suppose in BTR-IRV at each stage of elimination, after eliminating Y 
> because it was (between the two minTop count candidates X and Y) the 
> majority loser ... then instead of wasting that information, before 
> going on to the next step, you also eliminate each and every candidate 
> deemed (also by majority vote) to be inferior to Y ... how many 
> expensive steps might that save at zero cost?

Wouldn't this be very much like Benham? Suppose that X is the CW among 
uneliminated candidates, and the current bottom pairwise candidates are 
X and Y. Then X beats Y pairwise and X also beats everybody else 
pairwise, so X wins.

It may differ in which order it eliminates candidates in a 
three-candidate Smith cycle, though.

You mention Nanson and Baldwin. Is there any way of making a BTR-Carey? 
The only approaches I can think of (batch eliminate everybody with a 
below-average first pref score unless the ones who beat the candidate 
with first preference just above) feels artificial and may not even pass 
Condorcet. A Carey Benham would be easier: eliminate up from Plurality 
loser up to average Plurality score, but the moment someone is a CW 
among the remaining candidates, elect that candidate.

-km