Live data from Hacker News

A Solution of the P versus NP Problem?

arxiv.org

181–190 of 303 posts

Re: A Solution of the P versus NP Problem?

#181
post #174

If p != np, then comp sci will lose much of its appeal. There is an underlying hope behind the field that p = np, otherwise most problems of interest are intractable, and programmers are no longer masters of the universe. This is probably why there is not a proof yet, since the truth is undesirable.

No, all of cryptography is based on the assumption that P !=NP

Re: A Solution of the P versus NP Problem?

#182

Earlier quoted context omitted.

I don't think it would be possible to make finding it as easy as verifying it, but how can we prove that?

Someone should research and write a paper about it.

But then how will we know that paper is correct?

Re: A Solution of the P versus NP Problem?

#184

Earlier quoted context omitted.

Here is a largely correct ELI5: P != NP asks the question "Are problems that are easy to verify (NP) also Easy to solve ? (P)". Note that the reverse is obviously true : problems that are easy to solve are also easy to verify . Here is an example: Take the problem "Find minimum of 5,6,7,8". You solve the problem and tell me that the answer is 5. I can verify your answer by solving the problem myself, getting the the…

Also wanted to say: People have been taking a go at this for many years now. Grapevine says that several large CS departments in many countries have groups of graduate students devoted to solving sub-problems of the entire proof because it is a prestige issue. Extraordinary claims require extraordinary proof and any proof will go through multiple peer reviews. Perelman's proof of Poincare Conjecture was studied for s…

No TCS grad student I have talked to has had this experience...

Almost everybody in the field knows we're far from an actual proof with current techniques.

Re: A Solution of the P versus NP Problem?

#185

Earlier quoted context omitted.

The most interesting thing is if P=NP. If that's the case, that means that there is an algorithm that can solve any NP problem in polynomial time. This means that things like crypto would be able to be cracked in polynomial time which presents a huge problem for security. We basically operate under the assumption that P!=NP currently. Validation that this is true doesn't really change much. I can't speak to how this…

Would it present a problem for cryptography though? Quadratic algorithms are seen as already slow, cubic algorithms as unbearable garbage you best try to avoid if your data size is not tiny. And this completely ignores constant factors that can play a big role. Homomorphic encryption for instance fails to be usable just on a huge constant factor.

Yes, it would. The adversary in cryptography is assumed to be worst-case evil; it'll do whatever it can to break your algorithm, as long as it's performing a polynomial amount of computation. Remember, you're not just fighting your friendly neighborhood hacker, but possibly entire nation-states.

Re: A Solution of the P versus NP Problem?

#186
post #2

I would normally sigh and move on seeing such a claim, but this guy is an established senior researcher at the University of Bonn. A career-ending disaster or instant and eternal fame, that's some serious cahunas.

It shouldn't be career ending unless there's been malfeasance or some kind of sloppy work. The people who go down hard usually have some crime beyond audacity. It could easily cause some painful embarrassment, but hopefully that would pass with time. Maybe embarrassment similar to that faced by researchers who's results suggested FTL communication, but it turned out to be a bad fiber-optic cable. I didn't follow up b…

Agreed. Even in the event of the discovery of work which would qualify as minimally sloppy, I'd think his reputation (if not wanting of some polish) would still be intact after a quick retraction.

Re: A Solution of the P versus NP Problem?

#187

A list of 116 previous "solutions" to the P versus NP problem: http://www.win.tue.nl/~gwoegi/P-versus-NP.htm

The funny thing is that all these "solutions" are implications but not proof, and one contrary demonstration would actually render them all irrelevant as far as I understand the theory of computational p v np time complexity

Re: A Solution of the P versus NP Problem?

#188
post #162

A list of 116 previous "solutions" to the P versus NP problem: http://www.win.tue.nl/~gwoegi/P-versus-NP.htm

After skimming its interesting that the majority of the proofs in your list claim P equals NP. I would have guessed it would be more common for proofs to claim the opposite because P != NP makes sense intuitively. That being said it would certainly be more exciting if P did equal NP.

[deleted]

Re: A Solution of the P versus NP Problem?

#189
post #162

Earlier quoted context omitted.

After skimming its interesting that the majority of the proofs in your list claim P equals NP. I would have guessed it would be more common for proofs to claim the opposite because P != NP makes sense intuitively. That being said it would certainly be more exciting if P did equal NP.

A simple but wrong proof of "P = NP" is easier to write in some ways, since you "just" need to provide a single algorithm for one NP-hard problem, and show that it runs in polynomial time. It looks like many or most of the proof attempts in that list take this form. A plausible proof of "P != NP" won't be quite as simple to express, since it needs to prove that all such algorithms do not run in polynomial time.

Well yes! Two things: You have a successful algorithm that runs in P time that solves an NP Hard problem and 2) you can map other NP Hard problems to your problem. Without the second factor, it is only a demonstration of a "range" in the computational realm in question, where p = np or whatever the declaration. Being able to show that your pizza slice is actually an ocean of pizza, and also show that any other shape of pizza slice can be appropriately transformed into the shape you have means p = np. a "solution." Or perhaps better put, it is a funnel through which complex computational patterns can either be reduced or simplified or elegantly correlated, approaching absolutely perfect parallelization of operations. This is just one way to look at it, but essentially intractability is an interesting term to consider.

Please forgive me if my liberal use of the language is an offense

Re: A Solution of the P versus NP Problem?

#190
post #174

If p != np, then comp sci will lose much of its appeal. There is an underlying hope behind the field that p = np, otherwise most problems of interest are intractable, and programmers are no longer masters of the universe. This is probably why there is not a proof yet, since the truth is undesirable.

I'm not sure what you mean by "appeal." But, it seems to me that if P = NP, and if we can find a constructive proof of this fact, i.e. someone presents a P-time algorithm A_L deciding an NP-complete language L, the field of CS in a sense would get much less interesting, because although we would have answered arguably the most important question ever posed, there would be much less of a need to research and develop efficient algorithms or approximation strategies. We'd probably just focus on trying to improve the runtime of A_L and the reductions from other NP languages.
Post reply on HN