[EM] Is there a criterion for identical voters casting identical ballots?

[Scott Ritchie]

On Wed, 2006-12-13 at 21:06 +1030, Chris Benham wrote:
> 
> Scott Ritchie wrote:
> 
> >I was thinking about corporate elections today, and how under some
> >voting systems an individual would want to strategically vote by
> >submitting multiple, different ballots.  I soon realized that this was
> >generalizable to multiple voters with identical preferences in any
> >election.
> >
> >Basically, something like "If a group of voters share the same
> >preferences, then their optimal strategy should be to vote in exactly
> >the same way."
> >  
> >
> Scott,
> Are you referring to 0-info. strategy, or to informed strategy?
> 
> Chris Benham

Good point.  STV is only violated with informed strategy, I think
(though I may be wrong), while SNTV may be violated with 0 info.

Does "size of the electorate and of my group" count as information for
our purposes, or is information just the preferences of other voters?

Also, to be more specific, I am allowing the group to collaborate here
(ie, they have the information that their entire group is following the
strategy).  This is an important distinction, as it may allow the group
to know it is big enough to, for example, give an honest rather than
strategic second choice ranking (while an individual with the same
preferences might not).

Thanks,
Scott Ritchie