Dear Clinton, you wrote (14 Feb 2003): > Participation Monotonicity. > > If > (i) There is an election X in which option A wins. > (ii) There is a vote V ranks option A over option B. > (iii) There is an election Y identical to election X except that it has > an additional vote V. > then > Option B must not win election Y. > > What Participation Monotonicity says is, that participation will never > cause a less prefered option to win than non-participation. That is, it > is never advantagous to not participate.
The participation criterion and the Condorcet criterion are incompatible. (Proof: Herve Moulin, "Condorcet's Principle Implies the No Show Paradox," Journal of Economic Theory, vol. 45, pp. 53-64, 1988.) As far as I know, only point methods (e.g. plurality, Approval Voting, Borda) meet the participation criterion. Markus Schulze