[EM] No. Condorcet and Hare do not share the same problem with computational complexity and process transparency.

[Kristofer Munsterhjelm]

On 2024-03-26 00:42, Closed Limelike Curves wrote:
> On Mon, Mar 25, 2024 at 12:39 PM Richard Lung <voting at ukscientists.com 
> <mailto:voting at ukscientists.com>> wrote:
>> The non-monotonicity of STV just owes to it trailing a remnant of
>> plurality voting, in its "last past the post" exclusion count.
> 
> 
> No, the issue is the multi-stage method—the more elimination rounds you 
> have, the more likely you are to have a negative voting weight event. 
> Pretty much every sequential-loser method has the same problem.

Yes, though I think three candidates suffice for weighted positional. 
Say you have a Condorcet cycle, A>B>C>A, and the base method passes 
majority and monotonicity but fails either LIIA or strong monotonicity 
for three candidates. Then it's possible that raising A can lead the 
loser of the first round to go from C to B, e.g. the base method's 
ordering going from something like

B>A>C

to

A>C>B

which, in the context of an elimination method, means that in the 
original election, C is eliminated and then A beats B pairwise; but 
after A is raised, B is eliminated and C beats A pairwise.

"Strong monotonicity" is my term for the stronger mono-raise where 
raising A can't change whether the outcome ranks some other B ahead of 
C. Range passes it, for instance, but it's very rare in ranked methods.

I'm prettty sure you can prove such a strong monotonicity failure for 
every weighted positional method by using linear programming. And 
probably for a bunch of other methods as well.

>> The Surplus transfer election count, especially Meek method, is
>> monotonic.
> 
> That's also not correct; see Pukelsheim's book on apportionment for why 
> every quota rule method is nonmonotonic. I do think /most/ of STV's 
> nonmonotonicity comes down to the IRV elimination, though.

To my knowledge, his 2014 book only mentions house size monotonicity and 
vote ratio monotonicity. House monotonicity is compatible with quota. 
(Imagine a method that eliminates the one winner that won't cause a 
quota violation later on, and then continues doing so until the right 
number of seats has been reached.)

Vote-ratio monotonicity seems to be closer to mono-add-top, since 
Pukelsheim talks about a party's weight increasing while another party's 
weight is fixed at unity. I haven't looked into the proof in detail, but 
I suspect the reason that this works is because adding weight changes 
the value of the quota. Plain old mono-raise wouldn't do that, because 
the number of voters doesn't change.

(Here's an interesting thought: Set the elimination order to some 
predetermined order before running STV. Use the same logic: while 
someone has more than a quota, elect him and redistribute surpluses. 
Then eliminate the remaining candidate who's ranked last on the 
predetermined order, and repeat. Is this method monotone? Doing it like 
this would remove the IRV/strong monotonicity failure-related problems 
mentioned above.)

>> I have invented an STV exclusion count which is an iteration of the
>> election count; both therefore monotonic; a "scientific" one-truth
>> voting method, unlike other voting methods the world uses. I posted
>> programmers links, none of which, the list manager has so far redeemed.

I just downloaded the EM archives from 
http://lists.electorama.com/pipermail/election-methods-electorama.com/ 
to run a grep through the links and find any software links.

And I think this is it:

https://github.com/Esrot-Clients/STV_CSV/tree/master

referenced in this post:

http://lists.electorama.com/pipermail/election-methods-electorama.com/2023-October/004988.html

So it has already been posted :-)

-km