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Jan 5, 2023 at 6:34 comment added Aravindh Krishnamoorthy @GilKalai Thank you for the excellent answer. Would it be please possible to explain the following statement further: "A counterexample (which is not expected) may lead to a major change of our reality and not just our understanding of it." -> Do you mean the mathematical reality or computational complexity or something like the often-quoted (lay) example of music production (hard) vs discerning good music (relatively easy)?
Mar 29, 2021 at 21:13 comment added Gil Kalai Hi Lucia, thank you! Gil
Mar 27, 2021 at 19:10 comment added Lucia Hi Gil, I'd like to draw your attention to meta.mathoverflow.net/questions/4926/…
Oct 18, 2018 at 18:20 comment added Simd Why is it regarded as implausible that a proof that P=NP might give a $n^{1000}$ time algorithm for popular np-hard problems? I mean once you condition on the implausible assumption that P=NP.
Oct 18, 2018 at 17:30 history edited Martin Sleziak CC BY-SA 4.0
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Oct 29, 2015 at 16:01 history edited Gil Kalai CC BY-SA 3.0
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Oct 29, 2015 at 16:00 comment added Gil Kalai Joshua, When I say "certain" I do not mean "there exist" but rather certain specific algorithmic problem. I edit my answer to make it clearer.
Oct 29, 2015 at 15:56 comment added Joshua Grochow @GilKalai: I do not think P versus NP is the formulation - even morally - of the idea that certain algorithms require exponential time. The latter question is essentially P vs EXP, where we've known the answer for half a century. I think P versus NP is much closer to the formalization of the question of whether some algorithmic problems require brute force search (which is, conjecturally, just a small subset of EXP). However, perhaps the more relevant point is that whatever P vs NP formalizes, it is "just" a flagship conjecture indicative of a huge number of related open conjectures.
Feb 28, 2011 at 16:40 vote accept Andreas Thom
Feb 28, 2011 at 11:57 history edited Gil Kalai CC BY-SA 2.5
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Feb 4, 2011 at 22:11 comment added Suresh Venkat There's a whole thread of examples for this too !! cstheory.stackexchange.com/questions/4491/…
Feb 4, 2011 at 21:09 history edited Gil Kalai CC BY-SA 2.5
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Feb 4, 2011 at 15:36 comment added Timothy Chow @Andreas: There's the ellipsoid method for linear programming, and the fully polynomial randomized approximation scheme for the permanent.
Feb 4, 2011 at 7:08 comment added Andreas Thom Right. These examples show surprisingly good performance and a priori need exponential time. I was more asking for surprisingly bad performance and a priori polynomial time (but large constants).
Feb 4, 2011 at 0:08 comment added Suresh Venkat There's a whole thread of examples :) cstheory.stackexchange.com/questions/305/…
Feb 3, 2011 at 22:46 comment added Andreas Thom Thanks for this answer. Do you have other good examples where the asymptotic and the practical behavior (as you put it) differ drastically?
Feb 3, 2011 at 22:34 history answered Gil Kalai CC BY-SA 2.5