[EM] Improved versions of those 3 examples

Michael Ossipoff mikeo2106 at msn.com
Mon Mar 12 07:48:23 PDT 2007

I’d like to improve my three examples that I posted the other day, so that 
they’re genuine FBC failure examples for DMC.

In these examples, with DMC, either the B &/or C voters need to use informed 
Approval strategy to save the CW, enforce majority rule, and defeat the 
greater evil, or else one C voter could achieve that by burying his 

  52: AC (offensive order-reversal)
100: BA
  50: C/B

103: A
100: B
102: C/B

    3: A
100: BA
102: C/B

In the second two examples, the truncation examples, as before, DMC requires 
the use of informed Approval strategy to save the CW, enforce majority rule, 
and defeat the greater evil, while MDDA, MAMPO, and wv Condorcet don’t 
require any strategy at all.

Well, the exception now is that, in DMC, in all three examples, one C voter 
can accomplish those goals by voting B>C, burying his favorite. With these 
improved examples, there’s no other way he can achieve that.

Again, in the truncation examples, no one has to do anything to achieve 
those goals in MDDA, MAMPO and wv Condorcet.

To say what MDDA and MAMPO would do, using these ballots, I’m speaking of 
versions of those methods that use an Approval cutoff instead of saying that 
all ranked candidates are approved. That’s for the purpose of comparability 
with DMC using that balloting.

In the first example, with wv Condorcet, no one has to use any strategy to 
achieve those goals.
With MDDA, that one C voter could achieve it by merely voting B = C, in that 
example. With MAMPO, he couldn’t achieve it--but, as always with MAMPO & 
MDDA, there’s no incentive to favorite-bury. If approval by half the voters  
were enough to avoid disqualification, then that C voter could save the CW 
by ranking B = C. But the rules say that B is disqualified unless a majority 
approve him, and so that one C voter can’t save B in that example in MAMPO. 
Of course that’s good, because it won’t give him incentive to favorite-bury.

Mike Ossipoff

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