[EM] Approval-enhanced IRV (take 2)

[C.Benham]

This is I think more appealing and streamlined than my earlier version.

*Voter strictly rank from the top however many candidates they wish.

Also they can mark one candidate as the highest ranked candidate they 
approve.

Default approval is only for the top-ranked candidate.

Determine the IRV winner.

On ballots that approve the IRV winner, approval for any candidate or 
candidates
ranked below the IRV winner is withdrawn.

Elect the pairwise winner between the (thus modified) approval winner 
and the IRV
winner.*

This works fine in the same way as the earlier version in the example 
given to talk
about Minimal Defense and Chicken Dilemma.

It is more Condorcet efficient than normal IRV, and meets (or comes 
close enough
to meeting) appropriately modified versions of the LNHs and Minimal Defense
and Chicken Dilemma.

49 A  (sincere might be A>B)
24 B   (sincere might be B>C)
27 C>B

If the C voters B>A preference is strong they can by approving B avoid 
regret for not
Compromising.

Then the final pairwise comparison will be between B and A and B will win.

But if they are more concerned about not letting the B voters steal the 
election from
them by possible Defection strategy then they can do that by not 
approving B.

49 A>C>>B
48 B>>C>A
03 C>A>>B

Say this is for a seat in Parliament, and the voters have been 
accustomed to using FPP,
IRV or Top-Two Runoff. It would cross the mind of no-one that the 
"Condorcet winner"
C should defeat the IRV (and FPP and even Approval) winner A.

But according to Condorcet advocates the B voters should or could be 
regretting not
getting an outcome they somewhat prefer by all top voting C.

Well with this system the B and C voters together can "fix" this without 
anyone betraying
their favourites or reversing any sincere preferences simply by all of 
them approving C and
not A.  Then the final pairwise comparison will be between C and A with 
C winning.

Chris Benham