[EM] SFC and Conodrcet "full support of A>B and B>C at same time"

[Jobst Heitzig]

Warren Smith wrote:
> Ossipoff: But if Warren has a quibble about what it means to fully 
> vote X over Y, then
> I refer him to my criteria SFC, GSFC, and SDSC.
>
> --WDS: here is the definition of SFC given by Ossipoff (CW=Condorcet 
> winner):
> "SFC: If no one falsifies a preference, and there's a CW, and a 
> majority of all the voters
> prefer the CW to candidate Y, and vote sincerely, then Y shouldn't win."
> Ossipoff: "[SFC] is met by SSD and other good wv Condorcet versions."
> Ossipoff: "I call [SFC] the pinnacle of the promise of rank-balloting."
>
> However, Ossipoff is wrong. Here is a counterexample. There are 3 voters:
> A>B>C
> B>C>A
> C>A>B *
> where the * vote is insincere. The unstarred two voters are a "majority"
> who prefer the sincere-CW (who is B) over C, and who vote sincerely. 
> But the total vote
> is a 3-way perfect tie. Therefore C can win. But according to 
> Ossipoff's SFC, C cannot
> win. This counterexample works against every Condorcet method 
> satisfying anonymity.
Sorry, but you have overlooked the "no one falsifies a preference" 
clause: In your example, the third voter does falsify a preference.

Yours, Jobst