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A comment on I've reproduced 130 research papers about “predicting the stock market”.

Re:I've reproduced 130 research papers about “predicting the... by lidHanteyk on Friday August 16, 2019 @06:42PM (#20720413)
This is unsurprising. P likely is not equivalent to NP [0], and predicting the market is NP-hard [1]. It's nice to see empirical work in the field, though, and especially nice to see reproductions of published papers.

[0] https://www.scottaaronson.com/papers/pnp.pdf

[1] https://arxiv.org/abs/1002.2284

Edit for downvoters and repliers: If enough market participants are irrational, then it can still be possible for people to predict other people, instead of the market, and make money that way.

NP-hardness indeed doesn't rule out heuristic approaches, but experience with 3-SAT and other NP-complete problems suggest that there will be arbitrarily bad times, and that in those times, the amount of loss can be exponential in the length of time that the heuristic poorly predicts the market.

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Re:I've reproduced 130 research papers about “predicting the... by DennisP on Friday August 16, 2019 @09:19PM (#20721287)
Your second link doesn't say predicting the market is NP-hard. It says the opposite: that the market is only efficient if P=NP.

According to the paper, if you don't believe that P=NP then you believe that the market is inefficient, which means there's profit to be made. The paper even suggests how.

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Re:I've reproduced 130 research papers about “predicting the... by lucasmullens on Friday August 16, 2019 @06:50PM (#20720480)
What do you mean? People are successfully making millions or even billions on predicting the market. Seems like a stretch to relate this to P=NP
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Re:I've reproduced 130 research papers about “predicting the... by throwawaywego on Friday August 16, 2019 @06:49PM (#20720477)
You are talking about writing an algorithm that has a 100% accuracy on an NP-hard problem, and taking the impossibility of this to discard an approach that may yield 58% accuracy.
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Re:I've reproduced 130 research papers about “predicting the... by dvt on Friday August 16, 2019 @06:49PM (#20720471)
Philip Maymin seems like a serious guy... but that EMH ↔ P=NP paper is absolutely not even remotely a proof. Was genuinely very curious and it's at best an intuition. Some claims, e.g. Knapsack and 3SAT are (almost?) isomorphic to the efficient market hypothesis, are pretty bold. And the justification is hand-wavy at best.
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Re:I've reproduced 130 research papers about “predicting the... by kd0amg on Friday August 16, 2019 @09:30PM (#20721348)
It's not just hand-wavy. It's outright wrong. The size of the search space isn't just exponential in the amount of history -- that's the number of possible histories. The number of mappings from histories to positions is doubly exponential, so they can't even be uniquely described in less than exponential space.
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Re:I've reproduced 130 research papers about “predicting the... by pzone on Friday August 16, 2019 @09:45PM (#20721406)
He's not a serious guy at all, he's a nutjob who likes listening to himself talk.
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Re:I've reproduced 130 research papers about “predicting the... by pmaymin on Tuesday August 20, 2019 @03:57PM (#20751353)
Why must serious guy and nut job be my only two options. And why must they be mutually exclusive.
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Re:I've reproduced 130 research papers about “predicting the... by zazagura on Friday August 16, 2019 @07:07PM (#20720557)
Warren Buffet must have a secret proof of P=NP then, that would explain how he has made billions trading.
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Re:I've reproduced 130 research papers about “predicting the... by roguecoder on Friday August 16, 2019 @08:28PM (#20721007)
Warren Buffet is an interesting case, because his approach seems largely to consist of ways to reduce the N of what he is considering: choose a few bets, bet big, hold for the long term, choose bets where you already understand the market. Sampling, rarely recalculating and selecting subsets of N where the related data is already in cache are all well-understood techniques for addressing computationally-hard problems.
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Re:I've reproduced 130 research papers about “predicting the... by mrnobody_67 on Saturday August 17, 2019 @01:30PM (#20725103)
He's done a good job of avoiding expensive mistakes, not being pushed to invest cash in something marginal just because it's sitting there.

Half the battle is not doing something stupid.

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Re:I've reproduced 130 research papers about “predicting the... by IngvarLynn on Friday August 16, 2019 @06:59PM (#20720528)
NP-hardness is irrelevant here because algotrading is not 100% formalizable.
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