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the real question is why Pat left M18 on the table rather than buying up all the NO

Welp, this didn't work out :-(

I was wondering at what size would this break and was prepared to start a 2x (10/20 instead of 5/10 cooperation) market, but even the smallest one didn't demonstrate a cooperative "share" strategy

I'll think if I want to further experiment on different setups )

@NikitaSkovoroda I thought it was a fun experiment

I liked it. I was about to buy some YES but within seconds I saw Pat’s trade and was disappointed.

@NikitaSkovoroda thinking more markets would be created until no won was actually what made me decide to nip it in the bud

@PatMyron

Here i thought you just wanted to watch the world burn, but nipping self referential markets in the bud makes sense in the aftermath of WvM.

@ShitakiIntaki I personally have no problem with this kind of self-referential market where you can't manipulate the outcome solely by how much you spend. But fair.

@PatMyron Not very effective altruistic of you to thwart cooperation.

@PatMyron There was a cap on that, I didn't plan to create more than two actually )

But understandable and makes a good cause

@NicoDelon trying to save everyone's time on these zero-sum non-predictive markets 😉

@PatMyron That’s real effective altruism!

It's a NO then?

Cuz Pat bought NO.

@NikitaSkovoroda

@TobyBusickWarner sorry for the delay, I was asleep)

Expected this to be a bit faster

Thanks for the ping!

"Buying into the NO zone" -> do you just mean buying NO shares?

@jack No, buying YES and then buying some NO shares can still leave you in the YES zone or cancel out. I mean literally the right column on the "positions" tab, labeled as "NO payouts".

I might start a new market later with other rules that forbids that (and also selling, which is equivalent), but the language here doesn't forbid that.

Interesting steal or share game but I think this experiment is intended for a parimutuel market, the cpmm binary market provides fixed payouts. If the market is fixed at 3% the payout is in the neighborhood of 97:3 so no one would benefit from buying NO unless their utility function is just to watch the world burn, because everyone and each individual stands more to gain by cooperation buying YES.

@ShitakiIntaki I don't think your logic is correct, I might predict honestly that the probability of the coordination happening successfully is lower than the market price, in which case I would want to buy NO.

@jack I concede that there are traders that have a utility function which I have characterized as “watch the world burn” so this is absolutely a question as to whether the probability of coordination happening successfully is lower than the guaranteed return of opting to buy NO.

I am going to be uber embarrassed if my math doesn't check out after attempting to formalize my rational and ending up with this wall of text:

(TLDR - I had a greater confidence that traders would act rationally rather than capriciously. That being said, I suppose I was not very confident since I only invested M$ 1.)

I assume that a rational trader is willing to bet YES or NO, choosing the bet which has the highest expected payout. In contrast, we assume that an irrational trader selects the lowest expected payout. Then the probability at each step is a question of whether the trader believes that it will make rational sense for subsequent traders to buy YES or that subsequent traders will irrationally buy NO despite it making sense to buy YES.

Since the market resolves "immediately" once a trader buys NO, either to N/A in the case of the first five traders, or to NO after the first five traders, we can assume that any trader that is making a decision to buy YES or buy NO is the Nth trader following a succession of N-1 traders who have coordinated to buy YES.

Since the Market resolves on the 10th YES trader we start there.

Trader #10 is guaranteed to receive the payout on which ever outcome they select.  A rational trader will select the higher payout of 100/3 and choose YES as opposed to the payout of 100/97 for NO.

Trader #9 only has to decide if trader #10 will buy YES or not.  If trader #10 is rational then they will always pick YES, so #9’s EV is dependent upon what odds do the place on #10 acting rationally.  #9 is guaranteed a payout of 100/97 if they select NO so the EV YES needs only be greater than 100/97 if they are to rationally select YES.  The 100/3 market odds on YES has an expected value equal to the the guaranteed payout of NO (100/97) if #9 expects the odds that #10 acts rationally is 3/97 or less. (100/3 * 3/97 = 100/97)  There is only one trader to act after #9, so #9 does not require a very high confidence that a randomly selected trader #10 will act rationally to buy YES.

Trader #8 doesn't have to worry about coordination from traders #1 through #7, so they only need to concern themselves with whether or not trader #9 is rational or not.  Why doesn't trader #8 concern themselves with whether trader #10 is rational?  Because if trader #9 is rational they have already taken into account the rationality of trader #10.  If #9 is rational then there is a 3/97 chance they buy NO, in which case the game ends, and a 94/97 chance that they buy YES, so a rational #9 gives #8 an EV of (100/3 * 94/97), which is not reduced to the same level as the NO payout of 100/97 unless #8 has a confidence in the rational actions of #9 of 3/94 or less.

Similarly, Trader #7 has 100/3 * 3/91 EV YES assuming #8 is rational which would require a confidence of (3/97 * 94/91) or less that #8 is in fact rational to be less than the 100/97 guaranteed payout of NO.

The fractions get messier as you go through traders #6 to Trader #1 but the appear to be approaching a limit around 3.194854455%

Given that someone bought NO, I have to assume that they either acted rationally predicated upon a very low confidence that the average Manifold user will also act rationally or they enjoy “watching the world burn” as it were and are just having fun throwing a monkey wrench into the mix.

I had a greater confidence that traders would act rationally rather than capriciously. That being said, I suppose I was not really confident since I only invested M$ 1.

None of this takes into account price slippage as the instantaneous market rate changes when you buy shares of YES or how much YES anyone might buy and the reduction in their EV due to price slippage.

Counting this as a fixed mistake, not closing as N/A due to this.