Talk:IRV Prime: Difference between revisions
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Hello, Condorcet and Later-no-harm are incompatible - see proof in Woodall.<ref name="Woodall-Monotonicity">D R Woodall, [http://www.votingmatters.org.uk/ISSUE6/P4.HTM "Monotonicity and Single-Seat Election Rules"], ''[[Voting matters]]'', Issue 6, 1996</ref> Could you run your method through the example provided there and update the article? |
Hello, Condorcet and Later-no-harm are incompatible - see proof in Woodall.<ref name="Woodall-Monotonicity">D R Woodall, [http://www.votingmatters.org.uk/ISSUE6/P4.HTM "Monotonicity and Single-Seat Election Rules"], ''[[Voting matters]]'', Issue 6, 1996</ref> Could you run your method through the example provided there and update the article? |
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[[User:Kristomun|Kristomun]] ([[User talk:Kristomun|talk]]) 09:12, 31 July 2021 (UTC) |
[[User:Kristomun|Kristomun]] ([[User talk:Kristomun|talk]]) 09:12, 31 July 2021 (UTC) |
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== Arrow/IIA == |
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As I understand it, the reference to satisfying Arrow's theorem is meant to imply that the method satisfies IIA. But I don't think that's possible. |
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In a Condorcet cycle like this: |
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{{ballots| |
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35: A>B>C |
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30: B>C>A |
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25: C>A>B}} |
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Who wins in IRV Prime? If it's A, then eliminating B (irrelevant candidate) should make C win by majority rule. If it's B, then eliminating C makes A win; and if it's C, then eliminating A makes B win. I may be missing something, though! :-) [[User:Kristomun|Kristomun]] ([[User talk:Kristomun|talk]]) 22:22, 31 July 2021 (UTC) |
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Revision as of 22:22, 31 July 2021
Hello, Condorcet and Later-no-harm are incompatible - see proof in Woodall.[1] Could you run your method through the example provided there and update the article? Kristomun (talk) 09:12, 31 July 2021 (UTC)
Arrow/IIA
As I understand it, the reference to satisfying Arrow's theorem is meant to imply that the method satisfies IIA. But I don't think that's possible.
In a Condorcet cycle like this:
35: A>B>C 30: B>C>A 25: C>A>B
Who wins in IRV Prime? If it's A, then eliminating B (irrelevant candidate) should make C win by majority rule. If it's B, then eliminating C makes A win; and if it's C, then eliminating A makes B win. I may be missing something, though! :-) Kristomun (talk) 22:22, 31 July 2021 (UTC)
- ↑ D R Woodall, "Monotonicity and Single-Seat Election Rules", Voting matters, Issue 6, 1996