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Equilibrium analyses

CL
Closed Limelike Curves
Sat, Feb 24, 2024 7:39 PM

Does anyone know any papers that look at Myerson-Weber equilibria for
different systems? I know about Burt Monroe's "nonelection of turkeys"
paper, but not much else. I'd be very interested in any work on calculating
the regret for each method.

Does anyone know any papers that look at Myerson-Weber equilibria for different systems? I know about Burt Monroe's "nonelection of turkeys" paper, but not much else. I'd be very interested in any work on calculating the regret for each method.
MO
Michael Ossipoff
Sat, Feb 24, 2024 8:47 PM

Myerson’s & Weber’s own original paper that introduced it.

They showed that Approval’s MW equilibrium is at the voter-median (…where
the CW is).

They showed that Plurality (Vote-For-1) can have a MW equilibrium that
keeps on electing any pair of parties, however unliked, forever.

That sounds close to home.  …though our MW equilibrium is getting a lot of
help from the mass-media.

It was published in an economics journal, a major one. Econometrica?

Google Myerson & Weber, Voting Equilibrium.

On Sat, Feb 24, 2024 at 11:44 Closed Limelike Curves <
closed.limelike.curves@gmail.com> wrote:

Does anyone know any papers that look at Myerson-Weber equilibria for
different systems? I know about Burt Monroe's "nonelection of turkeys"
paper, but not much else. I'd be very interested in any work on calculating
the regret for each method.

Election-Methods mailing list - see https://electorama.com/em for list
info

Myerson’s & Weber’s own original paper that introduced it. They showed that Approval’s MW equilibrium is at the voter-median (…where the CW is). They showed that Plurality (Vote-For-1) can have a MW equilibrium that keeps on electing any pair of parties, however unliked, forever. That sounds close to home. …though our MW equilibrium is getting a lot of help from the mass-media. It was published in an economics journal, a major one. Econometrica? Google Myerson & Weber, Voting Equilibrium. On Sat, Feb 24, 2024 at 11:44 Closed Limelike Curves < closed.limelike.curves@gmail.com> wrote: > Does anyone know any papers that look at Myerson-Weber equilibria for > different systems? I know about Burt Monroe's "nonelection of turkeys" > paper, but not much else. I'd be very interested in any work on calculating > the regret for each method. > ---- > Election-Methods mailing list - see https://electorama.com/em for list > info >
KM
Kristofer Munsterhjelm
Mon, Feb 26, 2024 12:30 PM

On 2024-02-24 20:39, Closed Limelike Curves wrote:

Does anyone know any papers that look at Myerson-Weber equilibria for
different systems? I know about Burt Monroe's "nonelection of turkeys"
paper, but not much else. I'd be very interested in any work on
calculating the regret for each method.

There are some papers that analyze Nash and M-W voting equilibria for
voting methods, but they're usually very specific, as calculating Nash
over a multiplayer game with simultaneous moves is in general very hard.
(By multiplayer I mean more than two distinct players or types.)
Monroe's paper uses only two types of players, and I suspect that's the
reason.

Example of Nash equilibria in voting:
https://webdoc.sub.gwdg.de/ebook/serien/e/CORE/dp9931.pdf

https://www.nber.org/system/files/working_papers/w23898/revisions/w23898.rev0.pdf
(Chicken dilemma situation with more constrained behavior on the voters)

https://link.springer.com/article/10.1007/BF02425262 (sci-hub:
https://sci-hub.se/https://link.springer.com/article/10.1007/BF02425262)

https://link.springer.com/chapter/10.1007/978-3-642-02839-7_9 (sci-hub
analogous)

As for Monroe, I would further suspect that for some methods, modifying
a method X to be Condorcet//X instead will preserve NIA, but not for all
such methods. For instance, I'd imagine Condorcet//IRV passes and
Condorcet//Plurality fails. But again, I haven't proven this.

E.g. for Condorcet//IRV: Honest voting gives a tie between 1 and 2. If
any voter raises 3 to second to try to set up a cycle, the method falls
through to IRV, where 3 is still eliminated. This is basically DH3, and
C//IRV resists DH3 so it passes in this case.

Proving a single scenario doesn't prove the whole space, of course. It
would be interesting to determine if DMTBR (or electing from the
resistant set) implies Monroe's NIA, but I think doing so formally is a
bit out of my grasp. The converse, NIA->DMTBR, is false (see
Electowiki). Other interesting things would include proving e.g. DMTBR
implying resistant-efficiency.

In any case, it should be possible to analyze two-voter situations by
using linear programming. But I don't know of any papers where that has
been done more comprehensively.

-km

On 2024-02-24 20:39, Closed Limelike Curves wrote: > Does anyone know any papers that look at Myerson-Weber equilibria for > different systems? I know about Burt Monroe's "nonelection of turkeys" > paper, but not much else. I'd be very interested in any work on > calculating the regret for each method. There are some papers that analyze Nash and M-W voting equilibria for voting methods, but they're usually very specific, as calculating Nash over a multiplayer game with simultaneous moves is in general very hard. (By multiplayer I mean more than two distinct players or types.) Monroe's paper uses only two types of players, and I suspect that's the reason. Example of Nash equilibria in voting: https://webdoc.sub.gwdg.de/ebook/serien/e/CORE/dp9931.pdf https://www.nber.org/system/files/working_papers/w23898/revisions/w23898.rev0.pdf (Chicken dilemma situation with more constrained behavior on the voters) https://link.springer.com/article/10.1007/BF02425262 (sci-hub: https://sci-hub.se/https://link.springer.com/article/10.1007/BF02425262) https://link.springer.com/chapter/10.1007/978-3-642-02839-7_9 (sci-hub analogous) As for Monroe, I would further suspect that for some methods, modifying a method X to be Condorcet//X instead will preserve NIA, but not for all such methods. For instance, I'd imagine Condorcet//IRV passes and Condorcet//Plurality fails. But again, I haven't proven this. E.g. for Condorcet//IRV: Honest voting gives a tie between 1 and 2. If any voter raises 3 to second to try to set up a cycle, the method falls through to IRV, where 3 is still eliminated. This is basically DH3, and C//IRV resists DH3 so it passes in this case. Proving a single scenario doesn't prove the whole space, of course. It would be interesting to determine if DMTBR (or electing from the resistant set) implies Monroe's NIA, but I think doing so formally is a bit out of my grasp. The converse, NIA->DMTBR, is false (see Electowiki). Other interesting things would include proving e.g. DMTBR implying resistant-efficiency. In any case, it should be possible to analyze two-voter situations by using linear programming. But I don't know of any papers where that has been done more comprehensively. -km