[EM] Method X, bummer

[Forest Simmons]

Kevin,

Copeland is the simplest monotone Landau method.

Do we have a clone free version of Copeland that is for sure monotone?

Here's another one that (unlike Copeland) is definitely clone free as well
as monotonic (if my proof holds warer):

Initialize a candidate variable X as the highest approval candidate. Then
while X is covered, update X to be the most approved candidate that covers
the recent value of X that we are updating.

If I am not mistaken Agenda Based Chain Climbing is monotonic in the sense
that if the winner moves "up" the agenda without disturbing the relative
agenda order of the other candidates ... then the winner will still win.

If the agenda is based on approval scores, it seems to me that this
requirement should be met.

Am I wrong?

fws

On Sat, Aug 5, 2023, 11:11 AM Kevin Venzke <stepjak at yahoo.fr> wrote:

> Hi Forest, is IACC the same thing as TACC (i.e. initial head is the least
> approved)? Because I don't find TACC to be monotone.
>
> I actually don't know or haven't implemented any monotone Landau method.
> Not that I have really looked hard for one.
>
> Kevin
> (end)
>
>
> Le samedi 5 août 2023 à 12:21:22 UTC−5, Forest Simmons <
> forest.simmons21 at gmail.com> a écrit :
> Do you consider Implicit Approval Chain Climbing to be burial resistant?
>
> It certainly punishes the burying faction on all of the examples Chris
> gave highlighting his MinLosingVotes Pairwise Margins method.
>
> As a reminder it is the only Banks efficient monotone, clone independent,
> Universal Domain method that we know of so far.
>
> In general, Agenda Based Chain Climbing is monotone when the agenda
> formation is monotone ... so Borda and Kemeny Chain Climbing are also Banks
> efficient monotone methods that are probably burial resistant, but neither
> one is clone proof.
>
> In general, elimination with "take down" is Banks efficient ... but not
> monotone unless based on a fixed (no renormalization between eliminations)
> monotone agenda.
>
> Implicit Approval is monotone and clone proof and UD, but just barely UD.
> It is maddenly frustrating trying to find another UD monotone, clone proof
> agenda forming method.
>
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