[EM] Arrow's Theorem.
Eric Gorr
eric at ericgorr.net
Tue Jul 15 09:45:01 PDT 2003
At 9:22 AM -0700 7/15/03, Alex Small wrote:
>Eric Gorr said:
>> If Approval fails Arrow's Theorem in any example of an Approval
>> election, it simply fails Arrow's Theorem. Nothing more needs to be
> > said.
>
>A theorem says "Given these assumptions, this statement is true." Arrow
>assumes that the outcome is uniquely determined by a set of preference
>ballots (usually without equal rankings allowed, ar at least with
>non-binary preferences). Given that assumption, as well as 3 or more
>candidates, pareto, and non-dictatorship, Arrow proves that IIA is
>impossible to satisfy.
>
>Approval doesn't satisfy the assumption about an outcome uniquely
>determined from preference ballots.
It still seems to me that Approval does have preference ballots.
They are simply binary preferences (either you like the option or you
don't) from which an outcome (I assume this means winner) is uniquely
determined.
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