Markets are efficient if and only if P = NP · HackerPapers discussions

Markets are efficient if and only if P = NP — mentioned by silentmafia

Fri, 03 Jul 2026 15:59:06 GMT

A 2010 entry by the same author: Markets are efficient if and only if P = NP https://arxiv.org/abs/1002.2284 :)

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Markets are efficient if and only if P = NP — mentioned by eru

Sat, 26 Oct 2024 04:44:29 GMT

Thanks for the considered response. > "Markets are efficient if and only if P = NP": https://arxiv.org/abs/1002.2284 That's a very cute result, but requires a very specific definition of 'efficient market'. There's actually a range of 'efficient market' definitions, each with their own 'efficient market hypothesis'. One of the weaker forms that I like is: 'don't expect to make any money trading stocks as an amateur on news that the full time professionals (and their computers) in the hedge funds and at Goldman have already seen.' (This one is mostly useful for internet discussions with people…

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Markets are efficient if and only if P = NP — mentioned by ben_w

Fri, 25 Oct 2024 13:12:40 GMT

> No. Where do you get that misinformation? > Yes, it's relatively easy to construct a model where perfect information and a bunch of other assumption lead to markets being great. But that merely shows that these conditions are sufficient. Not that they are necessary. "Markets are efficient if and only if P = NP": https://arxiv.org/abs/1002.2284 To quote: """ I prove that if markets are weak-form efficient, meaning current prices fully reflect all information available in past prices, then P = NP, meaning every computational problem whose solution can be verified in polynomial time can also…

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Markets are efficient if and only if P = NP — mentioned by api

Tue, 03 Sep 2024 08:28:36 GMT

If markets were perfectly efficient there would be no entrepreneurs. To start a business of any kind is to hypothesize the existence of a market inefficiency, something the market is not currently doing that would make it more efficient. All business is in some sense arbitrage between state A, the market as it currently exists, and state B, the market with your business in it. A business succeeds if its hypothesis is correct and if it executes well. Also there's this: https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by samatman

Mon, 24 Jun 2024 16:47:32 GMT

The Efficient-market Hypothesis has been proven to be true only if P=NP. https://arxiv.org/abs/1002.2284 What's your bet on the latter? I'm... skeptical.

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Markets are efficient if and only if P = NP — mentioned by ben_w

Mon, 01 Apr 2024 20:54:53 GMT

> one where you can comfortably afford living, fun, saving, etc I think is most people's interpretations My understanding is that most people's understanding of "middle class" is "about 20% richer than me", and that this remains true regardless of how rich one is. Most people, for most of the years since Joseph Marie Jacquard realised he could control a loom with punched cards, the Red Queen race of automation has given us more stuff and experiences per hour of labour — if you wanted to live the 1820s idea of a middle class life, you can retire as soon as you get around €$£ 25-50k of savings…

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Markets are efficient if and only if P = NP — mentioned by j-pb

Mon, 28 Aug 2023 06:23:11 GMT

> The stock market provides an efficient medium for the allocation of capital. Only if P=NP.[1] Besides Efficiency: the ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in. This also begs the question: "To efficiently allocate capital (energy) for what goal (work)?" And it doesn't look like the answer to that is "the betterment of humanity", but to push the bell curve of wealth as far to the left as possible with the longest tail possible, externalities be damned. The stock market isn't a usefull tool for society like kickstarter, but…

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Markets are efficient if and only if P = NP — mentioned by eli_gottlieb

Mon, 08 May 2023 20:02:05 GMT

Ahahahahaha sure, if P=NP https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — HN submission

Mon, 16 May 2022 12:36:27 GMT

Markets Are Efficient If And Only If P = NP (2010)

4 points; 1 discussion reply on HN. Paper and source history. A submission is not an endorsement.

Markets are efficient if and only if P = NP — mentioned by DannyBee

Tue, 15 Mar 2022 02:41:04 GMT

Weak form efficiency - https://arxiv.org/abs/1002.2284 is one such proof. For strong form efficiency (which requires markets perfectly reflect all available information) - You would have trouble finding people who still believe in strong form efficiency. The weak form paper above cites several papers that go into why strong form efficiency is impossible. There are formal proof versions around. In practice, even empirical studies of strong form efficiency haven't supported it either - it's just very easy to find practical counterexamples.

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Markets are efficient if and only if P = NP — mentioned by j-pb

Fri, 01 Oct 2021 13:15:42 GMT

I think that's a pretty valid question to ask, but one that doesn't sit right with the typical neo-liberal/venture-capital clientele on HN. The wishful image of financial autonomy and chances of personal and business development through a public market seems to provide too much cognitive dissonance when confronted with the realities of how bloated, speculative, manipulated, and self-fulfilling stock markets have become. It's like telling someone who's put their entire live saving into bitcoin that it's a pyramid scheme. I mean any other idea would probably die on here, once it's been shown…

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Markets are efficient if and only if P = NP — mentioned by sudosysgen

Tue, 06 Jul 2021 23:38:49 GMT

I never said that central planning must work better or worse, just that Hayek's reasoning doesn't hold up because it starts from the ridiculous assumption that markets always find the equilibrium, always propagate local knowledge, etc.., and those are the reason why they theoretically are better than planning according to Hayek. I'm arguing against a purely theoretical argument that was cited with purely theoretical reasoning. The source for Hayek's assumptions implying P=NP is this : https://arxiv.org/pdf/1002.2284 I personally don't care for the purely theoretical arguments that Hayek…

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Markets are efficient if and only if P = NP — mentioned by sova

Sat, 24 Apr 2021 18:26:08 GMT

I don't know if you are a Computing Scientist, but you might find this parallel interesting: "Markets are efficient if and only if P = NP" https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by sudosysgen

Mon, 15 Feb 2021 18:43:05 GMT

Here is the article : https://arxiv.org/pdf/1002.2284.pdf I misremembered, it's not just the strong form that is refuted, but the weak form as well!

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Markets are efficient if and only if P = NP — HN submission

Wed, 21 Oct 2020 03:34:45 GMT

Markets are efficient if and only if P=NP (2010)

214 points; 169 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Markets are efficient if and only if P = NP — mentioned by ben_w

Sat, 26 Sep 2020 17:00:55 GMT

Only with perfect information, and even then markets are NP-complete. https://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by Fordec

Fri, 04 Sep 2020 23:46:06 GMT

Research paper: Markets are efficient if and only if P=NP https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by gonzo

Mon, 01 Jun 2020 04:19:44 GMT

the efficient market hypotheis isn't dead, but markets are efficient only if P == NP https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by lidHanteyk

Fri, 21 Feb 2020 11:50:58 GMT

Ah, you're one of those fools. When you're finished with history, try complexity theory [0]. [0] https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by sudosysgen

Tue, 21 Jan 2020 22:20:55 GMT

Here is a paper on it : https://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by aesthesia

Tue, 21 Jan 2020 22:19:34 GMT

Well, a naive, overly strong formulation of the efficient markets hypothesis may imply that P=NP. Something like "an optimal trading strategy is a function depending on the entire market history, and in order to find an optimal trading strategy, one must check an exponentially large space of such functions." The paper is here: https://arxiv.org/pdf/1002.2284.pdf. They do a sketchy reduction to an extremely stylized model of the market from the knapsack problem and 3-SAT.

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Markets are efficient if and only if P = NP — mentioned by api

Mon, 28 Oct 2019 21:14:18 GMT

Your second point could only be true if markets were infinitely intelligent. https://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by wahern

Wed, 11 Sep 2019 17:18:16 GMT

FWIW, someone took the time to formally state the case: "Markets are efficient if and only if P = NP", https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by lidHanteyk

Fri, 16 Aug 2019 22:42:27 GMT

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…

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Markets are efficient if and only if P = NP — mentioned by myWindoonn

Tue, 23 Apr 2019 01:01:31 GMT

Hi! I am a person who reads crankery. First, thank you for self-assessment. It's rare. This paper constructively suggests that P=NP iff EMH: https://arxiv.org/abs/1002.2284 It may be worth reading up on PPAD and Nash's thoughts on P=NP. Do not despair, but do not expect to be correct, either. Explore and be wrong, but look for proofs, too. Above all, do not forget that crankery is fundamentally about being unwilling to see existing proofs and results. Always try to open your mind.

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Markets are efficient if and only if P = NP — mentioned by rebeccaskinner

Thu, 07 Feb 2019 18:32:51 GMT

Markets are probably only efficient if P = NP, and it probably doesn't: https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by pjc50

Mon, 17 Dec 2018 20:38:47 GMT

> efficient markets are not deceptive markets. Participants are assumed to share equal information. Unfortunately this does not exist outside the textbook; there's an entire field devoted to information economics (Akerloff, Stiglitz et al). And then there's the brilliant "markets are efficient iff P=NP" paper: https://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by roguecoder

Fri, 10 Aug 2018 18:19:53 GMT

Even an efficient market will still have capital be more expensive for goods people disapprove of and aren't willing to support. An efficient market just means the price is discovered, not that the price solely reflects monetary outcomes. Plus there's probably no such thing as an efficient market; determining future outcomes of a market is an NP-complete problem and there are finite traders, so unless P equals NP you are definitely on the moral hook for the impact of your investment decisions. https://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — HN submission

Fri, 01 Jun 2018 06:04:59 GMT

Markets are efficient if and only if P = NP (2010)

332 points; 191 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Markets are efficient if and only if P = NP — HN submission

Tue, 26 Dec 2017 15:17:39 GMT

Markets are efficient if and only if P=NP (2010)

3 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Markets are efficient if and only if P = NP — mentioned by DannyBee

Thu, 19 Oct 2017 02:09:11 GMT

Well, actually, they kinda do. Also, https://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by nullc

Fri, 21 Apr 2017 07:46:12 GMT

I dug it up for you: https://arxiv.org/abs/1002.2284 I thought it was fun.

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Markets are efficient if and only if P = NP — mentioned by pjc50

Fri, 08 Apr 2016 09:53:19 GMT

I don't see why you're being downvoted. Here's a reference for market pricing being almost certainly NP-hard: http://arxiv.org/pdf/1002.2284 "Markets are efficient if and only if P = NP"

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Markets are efficient if and only if P = NP — mentioned by fiatmoney

Wed, 08 Jul 2015 15:31:15 GMT

There was a nice result a while back that the efficient market hypothesis is true IFF P=NP. http://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by noblethrasher

Thu, 13 Nov 2014 23:49:46 GMT

"Markets are efficient if and only if P = NP"[1] I read it when it was first posted on HN a few years ago. [1]http://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by DannyBee

Tue, 26 Aug 2014 21:28:36 GMT

" a lot of competitors with essentially same product and everyone instantly know all available into (so everyone buys cheapest of the same)." But we already know these free markets are either not efficient or likely not efficient. Strong form efficiency is provably false. Weak form efficiency is only possibly true if P = NP (http://arxiv.org/abs/1002.2284).

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Markets are efficient if and only if P = NP — mentioned by warfangle

Tue, 15 Jul 2014 14:29:03 GMT

(edited for source) There is no such thing as a free market: it is an idealistic theoretical construct. And even if it were real, it would only be efficient if P=NP[0]. 0. http://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by Dewie

Thu, 20 Feb 2014 21:45:19 GMT

This might be slightly relevant here: http://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by m0th87

Tue, 22 Oct 2013 03:37:38 GMT

For starters, markets cannot be perfectly efficient unless P = NP: http://arxiv.org/pdf/1002.2284.pdf

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Markets are efficient if and only if P = NP — mentioned by gte910h

Fri, 05 Oct 2012 23:38:53 GMT

Markets are only efficient if P=NP. We do not seem to think that's the case. http://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — HN submission

Wed, 03 Oct 2012 19:12:44 GMT

Markets are efficient if and only if P = NP

1 point; 1 discussion reply on HN. Paper and source history. A submission is not an endorsement.

Markets are efficient if and only if P = NP — mentioned by brador

Sat, 29 Sep 2012 11:52:09 GMT

Direct link: http://arxiv.org/pdf/1002.2284v2 [PDF]

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Markets are efficient if and only if P = NP — HN submission

Sat, 29 Sep 2012 11:09:58 GMT

Markets are efficient if and only if P = NP

107 points; 123 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Markets are efficient if and only if P = NP — HN submission

Sun, 12 Feb 2012 00:48:36 GMT

Markets are efficient if and only if P = NP

9 points; 1 discussion reply on HN. Paper and source history. A submission is not an endorsement.

Markets are efficient if and only if P = NP — mentioned by lyudmil

Fri, 01 Apr 2011 15:37:50 GMT

It would be a boon for laissez-faire capitalism, as it would prove that markets are at least weak-form efficient. Reference: http://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — mentioned by loewenskind

Mon, 16 Aug 2010 12:37:21 GMT

> Efficient markets have already priced in all these well known reasons for one. Too bad there's no such thing as an efficient market [1]. [1] http://arxiv.org/abs/1002.2284

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Markets are efficient if and only if P = NP — HN submission

Sun, 14 Feb 2010 16:23:02 GMT

Markets are efficient if and only if P = NP

6 points; 2 discussion replies on HN. Paper and source history. A submission is not an endorsement.