[EM] SARC definition improvement

[Markus Schulze]

Dear Mike,

you wrote (23 Aug 2000):
> I defined the criterion SARC here some time ago, but I've more
> recently been using a slightly different definition. The difference
> is minor, but the previous definition allowed some methods to be
> outside of SARC's application. The new definition applies to all methods.
>
> Improved SARC definition:
>
> If a group of voters share the same preferences, and they vote in the
> same way, and they vote in a way that isn't dominated by any other way
> of voting, then the fact that they showed up & voted in that way should
> never cause their favorite to lose, or cause their last choice to win,
> if that wouldn't have happened had they not showed up & voted.
>
> For some particular voter, a way of voting (V1) dominates another way
> of voting (V2) if there's some configuration of the other people's votes
> for which that voter prefers the result when he votes V1 to the result
> when he votes V2, but there's no configuration of the other people's
> votes for which he prefers the result when he votes V2 to the result
> when he votes V1.
>
> Again, Approval is the only voting system that passes SARC.

Could you please post an example showing Borda violates SARC?

Markus Schulze
schulze at sol.physik.tu-berlin.de
schulze at math.tu-berlin.de
markusschulze at planet-interkom.de