Sigh. Cheers, RAH ---------- <http://arxiv1.library.cornell.edu/abs/1002.2284>arXiv.org > q-fin > arXiv:1002.2284 Quantitative Finance > General Finance Markets are efficient if and only if P = NP Philip Maymin (Submitted on 11 Feb 2010) 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 be solved in polynomial time. I also prove the converse by showing how we can "program" the market to solve NP-complete problems. Since P probably does not equal NP, markets are probably not efficient. Specifically, markets become increasingly inefficient as the time series lengthens or becomes more frequent. An illustration by way of partitioning the excess returns to momentum strategies based on data availability confirms this prediction. Subjects: General Finance (q-fin.GN); Computational Complexity (cs.CC) Cite as: arXiv:1002.2284v1 [q-fin.GN] Submission history From: Philip Maymin [view email] [v1] Thu, 11 Feb 2010 05:56:16 GMT (46kb,X) Which authors of this paper are endorsers? Link back to: arXiv, form interface, contact.