[EM] Arrow's Theorem.

[Eric Gorr]

At 11:04 AM -0500 7/15/03, Adam Tarr wrote:
>Eric Gorr wrote:
>
>>The point is that if Plurality is covered by Arrow's Theorem, then 
>>so is Approval since if in an Approval election the voters only 
>>vote for a single option, that election would be equivalent to a 
>>Plurality election.
>
>It does not necessarily follow.  The point is, the results of a 
>plurality election can be _uniquely determined_ from a set of 
>preference ballots.  In contrast, a common criticism of approval is 
>that the results cannot be derived from voters' preference orders.

And, in the case where the voters in an Approval election only vote 
for a single option, the same would be true.

>>So, the question becomes, does Plurality fail Arrow's Theorem?
>>
>>I believe the answer to this question is 'Yes'.
>
>I agree with this.

Good...at least I can feel more confident on one point. :-)