[EM] Woodall Tests (was Realism of Tideman vs Schulze numerical testing)

David Catchpole s349436 at student.uq.edu.au
Sun Nov 5 14:05:29 PST 2000

(3) is just Pareto efficiency worded weirdly. It doesn't fail

On Sat, 4 Nov 2000 DEMOREP1 at aol.com wrote:

> there is a paper by Woodall in which he demonstrates that
> no preferential single-winner election method can meet the
> following four properties simultaneously [Douglas R. Woodall,
> "An impossibility theorem for electoral systems," Discrete
> Mathematics, vol. 66, p. 209-211, 1987]:
> 1) monotonicity;
> 2) later-no-help and later-no-harm;
> 3) if no second preferences are expressed and candidate A
>    has a plurality of first preferences, then candidate A
>    must be elected;
> 4) if more than half of the voters strictly prefer candidate
>    A and candidate B to every other candidate, then either
>    candidate A or candidate B must be elected.
> Which of Woodall's properties would you be prepared to see
> not satisfied by your preferred system?
> -----
> D- How many of such tests relate to YES/NO, head to head and/or place votes 
> tables ???
> Test 3) fails simple majority rule.
> Test 4) seems to be a variant of YES majority votes.

"I only said we'd make it across"
				-"Road Trip"

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