[EM] Generalizing "manipulability"

[Juho Laatu]

--- On Sun, 18/1/09, Jonathan Lundell <jlundell at pobox.com> wrote:

> On Jan 17, 2009, at 4:31 PM, Juho Laatu wrote:
> 
> > The mail contained quite good
> > definitions.
> > 
> > I didn't however agree with the
> > referenced part below. I think "sincere"
> > and "zero-knowledge best strategic"
> > ballot need not be the same. For example
> > in Range(0,99) my sincere ballot could
> > be A=50 B=51 but my best strategic vote
> > would be A=0 B=99. Also other methods
> > may have similarly small differences
> > between "sincere" and "zero-knowledge
> > best strategic" ballots.
> 
> My argument is that the Range values (as well as the
> Approval cutoff point) have meaning only within the method.
> We know from your example how you rank A vs B, but the
> actual values are uninterpreted except within the count.
> 
> The term "sincere" is metaphorical at best, even
> with linear ballots. What I'm arguing is that that
> metaphor breaks down with non-linear methods, and the
> appropriate generalization/abstraction of a sincere ballot
> is a zero-knowledge ballot.

I don't quite see why ranking based
methods (Range, Approval) would not
follow the same principles/definitions
as rating based methods. The sincere
message of the voter was above that she
only slightly prefers B over A but the
strategic vote indicated that she finds
B to be maximally better than A (or
that in order to make B win she better
vote this way).

Juho



> 
> > 
> > 
> > Juho
> > 
> > 
> > --- On Sun, 18/1/09, Jonathan Lundell
> <jlundell at pobox.com> wrote:
> > 
> >> The generalization of a "sincere" ballot
> then
> >> becomes the zero-knowledge (of other voters'
> behavior)
> >> ballot, although we might still want to talk about
> a
> >> "sincere ordering" (that is, the sincere
> linear
> >> ballot) in trying to determine a "best
> possible"
> >> outcome.