[EM] a simple, great ISDA-compliant method I've never seen mentioned

[Filip Ejlak]

Hello, everyone, new to the list here,

what I really like about First preference Copeland is that it implies a
nice method for calculating a sort of "Condorcet score": just count 1st
preferences of all candidates (including candidate X) that do not beat X
pairwise. Although it is highly resistant to burial, FPC is not cloneproof
and fails ISDA.

However, there is an easy way to fix these two problems: just do sequential
loser elimination using FPC score!
(And when there is a tie at the bottom, break it by applying the same
method to the candidates involved in the tie and finding the loser.)

This method could be named FPCE (First Preference Copeland Elimination) or
ISCR (Instant Simmons-Copeland Runoff). It is cloneproof (because even if
there are clones which hurt one another, eventually there is only one of
them left) and ISDA-compliant (because all candidates outside the Smith set
get eliminated before any Smith set member is eliminated). I think its
burial resistance might be weakened, though, as it fails DMTBR.

Could anyone help with proving/disproving monotonicity, or even LIIA? I
applied the method to the 5-candidate Smith set from the Wikipedia article
about Schulze and there turned out to be an LIIA-compliant order: ADCEB.
I'm curious if it was by accident or not.

Filip Ejlak
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