[EM] Strategy-proof vs Monotone

[Kristofer Munsterhjelm]

On 19.01.2022 22:16, Richard Lung wrote:
> 
> km,
> You are repeating what the rest of my post already says -- the need
> for testing in realistic scenarios. -- Not so much to test monotonicity
> and strategy resistance. That is guaranteed by the removal of the ad hoc
> premature exclusion of candidates. And replacing it with an exclusion
> count, symmetrical to, or exactly the same as the election count,  That
> is a transferable vote, known to be monotonic -- and hence so, in an
> exclusion count as well as an election count.

You are saying that a particular procedural mechanism ensures
monotonicity and strategy resistance. I doubt that this can be inferred
simply from procedural design, because it's very easy to come up with
something that seems right but turns out to have a subtle weak spot.

I would like to have an implementation so that I could at least see
whether a computer search could find any monotonicity failures, and so
that the strategy resistance could be indicated in a similar way to what
Daniel is doing.

That's what I'm saying. Of course surprise is not an argument; I am
simply saying that, in the absence of anything more conclusive and
readily available, my experience is all I've got, and that experience
indicates that monotonicity in STV is very difficult, and that monotone
strategy resistance is even more difficult.

That is not a proof that your method isn't monotone, but I didn't claim
that it constituted such a proof. Just that when you keep saying that
your STV method (unlike other STV methods) is provably monotone, I would
like to see the goods for myself, as it were.

-km