[EM] "More often" (was: IRV and Condorcet operating identically)

[Markus Schulze]

Dear Steph,

the participation criterion says that it is not possible
to worsen the outcome by participating:

   Suppose that candidate A is the winner. Suppose that
   a set of voters, where each voter strictly prefers
   candidate B to candidate A, is added to the original
   profile. Then candidate B must not become the new winner.

Moulin demonstrated that the Condorcet criterion and the
participation criterion are incompatible. (Herve Moulin,
"Condorcet's Principle Implies the No Show Paradox,"
Journal of Economic Theory, vol. 45, pp. 53-64, 1988.)

Markus Schulze

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