[EM] cloneproof[strat2-revote]

[Warren Smith]

cloneproof[strat2-revote]

A voting method hereby is "cloneproof[strat2-revote]" if W'=W when:
1. We hold an election with strategic voters, electing winner W.
2. we add clones (perhaps multiple clones) of some subset of the candidates.
3. The voters re-vote in the new election, again acting strategically
in the new scenario.  We get winner W'.

In contrast, a voting method is "cloneproof" if U'=U when:
1. We hold an election, electing winner U.
2. we add clones (perhaps multiple clones) of some subset of the candidates.
3.  The originally submitted votes are altered to include the clones
equal to (or if that is impossible, adjacent to) their originals.
(If adjacent, then this has to work regardless of the adjacencies' combinatorial type.)
4. Using these altered votes, we use the election method to deduce winner U'.

The thread started with the claim DMC was cloneproof.
I pointed out that range voting was cloneproof.
Benham responded that range voting was not cloneproof[strat2-revote].
I responded that DMC was (almost certainly) also not cloneproof[strat2-revote],
and neither were most voting methods normally touted as being "cloneproof."

(We can similarly create a [strat2-revote] version of a lot of other
voting system properties, and this often changes the assessment.)

wds