[EM] Re: Methods passing or failing INI

[Richard Moore]

Markus Schulze wrote:
> Dear Richard,
>
> suppose d[X,Y] is the number of voters who strictly prefer
> candidate X to candidate Y.

First, let's clarify that "prefer" here refers to preferences as 
expressed on ballots (otherwise this criterion wouldn't be testable).

> I suggest the following criterion ("Independence from
> Nonsupporting Pareto-Dominated Alternatives"; INPDA):
>
>    Adding candidate Z with d[A,Z] > 0 and d[Z,A] = 0
>    must not change candidate A from a winner to a loser.
>
> Tideman's ranked pairs method violates this criterion while
> my beatpath method satisfies this criterion. Hehehe.

Hmm, so does IRV. Not a very discriminating criterion, is it?

  -- Richard