I would have thought that EMH was much stronger. Just as you can come up with market problems that are NP-complete, it seems to me that you should be able to come up with non-Turing-computable market problems, so that full efficient markets would be required to solve uncomputable problems.
I'm not sure exactly what you are saying, but I think you must be addressing an entirely different issue from what this paper is addressing.
His claim is that you can solve any problem in NP in polynomial time just by placing trades on the open market and watching what happens to the asset prices, if the weakest efficient market hypothesis is true. Conversely, he also claims that if P=NP, then the weak efficient market hypothesis must be true (this seems far more believable).
So when you say you'd have thought the EMH is "must stronger", are you talking about the strong EMH (if so, he's not even considering that in the paper)? And assuming you think it's plausible that the weak EMH is true, do you really think you can exploit that to solve NP-hard problems?
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timeasmymeasure
no subject
Date: 2010-03-08 12:37 am (UTC)I would have thought that EMH was much stronger. Just as you can come up with market problems that are NP-complete, it seems to me that you should be able to come up with non-Turing-computable market problems, so that full efficient markets would be required to solve uncomputable problems.
I'm not sure exactly what you are saying, but I think you must be addressing an entirely different issue from what this paper is addressing.
His claim is that you can solve any problem in NP in polynomial time just by placing trades on the open market and watching what happens to the asset prices, if the weakest efficient market hypothesis is true. Conversely, he also claims that if P=NP, then the weak efficient market hypothesis must be true (this seems far more believable).
So when you say you'd have thought the EMH is "must stronger", are you talking about the strong EMH (if so, he's not even considering that in the paper)? And assuming you think it's plausible that the weak EMH is true, do you really think you can exploit that to solve NP-hard problems?