[EM] Simmons' "solution" of voting system design puzzle is inadequate

Chris Benham chrisjbenham at optusnet.com.au
Sat Jan 20 14:00:40 PST 2007



Warren Smith wrote:

>Here is the current CRV web page about this problems and its (lack of) solution
>
>We are speaking about puzzle #5 at
>http://www.rangevoting.org/PuzzlePage.html
>
>---
>
> Puzzle #5: Voting systems immune to clones and avoiding favorite-betrayal
>
>Puzzle:
>Two desirable properties of a voting system - both of which Range Voting has - are "immunity to candidate-cloning" (ICC) and "avoiding favorite betrayal" (AFB).
>AFB: voters should never have strategic incentive to "betray" their favorite candidate by voting him below some other.
>ICC: political parties should be unable to usefully manipulate an election by running clones of their own, or of an opposed, candidate; voters here are assumed to vote honestly and to have only tiny preferences (which they may express in their votes, if they exist) among the clones.
>
By this definition Range fails "ICC" because voters can only express 
preferences among clones by not giving maximum possible score to all of 
them, thus making it
possible that if a narrow winner is replaced by a set of clones all the 
clones lose.

>Note: Many voting systems are known (beyond just variants of range voting) which satisfy AFB
>
Many?  There is MCA,  ER-Bucklin(Whole),  one or two Kevin Venzke 
methods and what else?


Chris Benham










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