Exaggerated opinions

[Markus Schulze]

Dear David,

you wrote (28 Apr 1998):
> The tempted voters are faced with a game in which their minimax 
> strategy is to vote according to their true preferences.
> 
> Conjecture A: Condorcet/Dodgson meets this.
> 
> Conjecture B: Only Condorcet/Dodgson meets this. (Not so sure about 
> this one!)
> 
> I have a proof of A for slightly different criteria. I'm not sure 
> about B, but the alternatives I've looked at fail.

The Dodgson method has two major problems:
1) It is NP-hard; i.e., the winner cannot be calculated in a
   polynomial time.
2) It fails to meet clone criteria.

Although -if the Dodgson method is used- it is difficult for the
voters to vote tactically, it is very simple for the parties to
manipulate the result of the elections by nominating clones.

Markus


P.S.: Those people, who don't know the Dodgson method, should read

1.) D. Black, "The Theory of Committees and Elections," Cambridge
    University Press, 1958,
2.) J. Bartholdi III, C.A. Tovey, and M.A. Trick, "Voting schemes
    for which it can be difficult to tell who won the election,"
    Social Choice and Welfare, vol. 6, p. 157, 1989.