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Jun Fukuyama's P≠NP Page

junfukuyama.wordpress.com

41–50 of 85 posts

Re: Jun Fukuyama's P≠NP Page

#41
post #8

Earlier quoted context omitted.

If I had the mathematical background necessary to understand it, I certainly would. ... and I really wish I did have the mathematical background. Anyone have any recommendations on how to go from a standard CS undergrad math background to being able to understand proofs like these?

Read it and google as you go. Math is one of the best covered topics online. For a potential millenium prize proof, it seems very approachable. That said, that's not saying much.

I find math in some cases to be really hard to Google. Particularly with expressions that I don't know the names of; I never know what to use as search terms.

Re: Jun Fukuyama's P≠NP Page

#42

Earlier quoted context omitted.

Toyota actually has opened a school in Chicago specifically for computer science, in conjunction with the University of Chicago: http://en.wikipedia.org/wiki/Toyota_Technological_Institute_...

I go to UChicago; that place is sort of like an eerie mystery box that nobody ever goes to or talks about. I didn't even find out about it's existence until my 3rd year here. My one friend who's been in there described the experience as really bizarre; it left him half convinced that its actually a front for some sort of Israeli money laundering operation.

Please encourage him to blog on it and post to HN. Sounds entertaining.

Re: Jun Fukuyama's P≠NP Page

#43
post #40

Earlier quoted context omitted.

If I understand it right he showed that Clique cannot be solved in polynomial time, since any NP complete problem is at least as hard as Clique none of those problems can be solved in polynomial time. So he used Clique to draw general conclusion that P!=NP.

This only works if all NPC problems can be converted to CLIQUE?

All NP problems can be converted into the other NP problems, therefore if you can prove it for one NP problem, you prove it for all NP problems.

Re: Jun Fukuyama's P≠NP Page

#44

Very briefly: Context: Some problems are easy, and known to be easy. Some problems appear to be hard, and yet easy to verify alleged solutions. That seems odd - let's have a closer look. Example: Consider being given a network and asked if there's a path that visits every node exactly once and returns to its starting point. (This is the task of asking if a Hamilton Cycle exists). If the network is big enough, decidin…

After reading this response and then reading your profile all I would like to say is thank you for contributing to HN. I certainly appreciate it, your karma count leads me to believe many others appreciate it, and I hope you don't let the vocal minority successfully disuade you from it.

Re: Jun Fukuyama's P≠NP Page

#45
post #35

Earlier quoted context omitted.

Yes, that's what he is saying, every CLIQUE algorithm takes at least exponential time.

Oh ok, I thought the first post was referring to a single algorithm, not every possible algorithm. My mistake.

Sorry, if I could I would edit it to be more clear. We definitely need to show that no algorithm can exist with poly runtime for all inputs.

Re: Jun Fukuyama's P≠NP Page

#46
post #43
post #40

Earlier quoted context omitted.

This only works if all NPC problems can be converted to CLIQUE?

All NP problems can be converted into the other NP problems, therefore if you can prove it for one NP problem, you prove it for all NP problems.

You missed a few words. Any NP-complete problem can be converted into any other NP-complete problem in polynomial time.

Re: Jun Fukuyama's P≠NP Page

#47

Can we get a laymans explanation of what this is about? I understand what p np is, but don't really understand what this person is claiming. Is this some kind of claim about the overall concept of p np? Or proving a specific case?

I think he is showing the clique problem cannot be solved in polynomial time. Since clique is in NP and not P, P!=NP.

The claim is that since clique is in NP-complete and not P, P != NP. (Every problem in P is in NP.)

Re: Jun Fukuyama's P≠NP Page

#48

Earlier quoted context omitted.

Toyota actually has opened a school in Chicago specifically for computer science, in conjunction with the University of Chicago: http://en.wikipedia.org/wiki/Toyota_Technological_Institute_...

I go to UChicago; that place is sort of like an eerie mystery box that nobody ever goes to or talks about. I didn't even find out about it's existence until my 3rd year here. My one friend who's been in there described the experience as really bizarre; it left him half convinced that its actually a front for some sort of Israeli money laundering operation.

They have some very prominent machine learning folks there and I went to the Machine Learning Summer School they hosted a few years back. Seemed legitimate enough to me!

Re: Jun Fukuyama's P≠NP Page

#50
Before anyone gets too excited, I would caution that there there is a long history of failed attempts at this problem, and an equally long history of premature announcements. On the surface, here is what is encouraging about this one:

- The author is a theory professional and not an amateur or a crank

- The author frames this as a possible proof where he's seeking feedback on the method, rather than declaring a solution up front

- The author builds on existing theory in a formerly mainstream approach that has been shown to have problems (circuit lower bounds)

- Looks like a serious and well-considered proof effort

Here is why HN should hold off on any excitement:

- This style of proof was found to be unworkable in the past. In particular, approaches to proving circuit lower bounds in this manner were shown by Razborov and Rudich to be "natural proofs" in the 1990s, which is a category of proof strategy that cannot demonstrate P/NP. It's not explained why this strategy does not succumb to the same problem -- though the author surely has some reasoning around it. (see point 6 of Scott Aaronson's "8 signs a proposed P/NP proof is wrong": http://www.scottaaronson.com/blog/?p=458. You might also see this comment from /r/math: http://www.reddit.com/r/compsci/comments/14mqqt/anyone_have_...) ).

- There is a very good community framework for evaluating proposed solutions when the author's ready. Possibly the author has already submitted the work to a journal, but it's not clear that he's confident enough yet to invite more active discussion on his effort from the theory community. I can't find any discussion of it online. It's likely he's pursuing these on his own, and conceivably flaws have been found since the summer.

- The author does not declare this as a completed solution in the same way that Deolikar did two years ago. In that case, his announcement led to an analysis by the theory community online that led to discovery of core errors. We can wait here 'til the author gives a bit more information.

- This proof joins dozens of other announced solutions to P/NP in both directions (see, for example, http://www.win.tue.nl/~gwoegi/P-versus-NP.htm) which emerge quite regularly, and close attention paid to each will leave no time for original research :)

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