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P ≠ NP

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Re: P ≠ NP

#151
post #147

This is sad: This result, if correct, is the mathematical result of the century; however, it still hasn't appeared in Google News or Google trends.

It's a leaked PDF of an unverified proof which has yet to appear in any mainstream news source and is relevant, probably, to no one but computer scientists. So it's not even remotely surprising that it has not yet appeared on Google News. I have no idea what part of this you think is sad.

Re: P ≠ NP

#152
post #40

I skimmed through the synopsis but this philosophical statement baffles me (although obviously it is unrelated to the validity or invalidity of the proof): "The implications of [P ?= NP] on the general philosophical question of [..] whether human creativity can be automated, would be profound." How so? If P!=NP, that is obeyed by the brain as much as by computers and whatever trick our brains does to be creative desp…

In order to automate human creativity one must understand its nature at least.

Re: P ≠ NP

#153
post #119

Earlier quoted context omitted.

"only certain proof strategies" is technically correct, but its closer to "essentially every proof strategy we can conceive of". And besides, the question is over the entire proof strategy and not the specific techniques involved. It seems plausible that one could give a relativizing proof using some method of calculation from statistical mechanics, for example.

Again, I'm no expert, but relativization and algebrization are properties of proofs that invoke oracles, which this paper doesn't appear to do.

Ah, that is not how those "barriers" work. Roughly, the relativization barrier goes like this: Say you have a proof that P!=NP. Does it also prove that P^A != NP^A for any oracle A? If it does, then the proof is flawed, because there does exist an oracle A such that P^A = NP^A!

Such proofs are said to relativize -- i.e., they are still valid relative to any oracle.

Re: P ≠ NP

#154
post #69
post #50

Earlier quoted context omitted.

While I agree P != NP doesn't say anything about human creativity, but the reason it can't be automated is, I think, different: creativity is closely tied to libido and biological evolution, which in turn can't be simulated in machines in full.

I'd argue that if (assuming it's true that) creativity stems from libido and biological evolution, it's been because there are evolutionary gains for creative individuals. The first person to throw a rock at a tree to knock down fruit got more food, for instance. The most complicated clothing (/nest/dance) gets the most mates. All of which means it's purely a motivating force , not a requirement . We've been motivate…

What I actually meant was what we create rather than why.

Re: P ≠ NP

#155
post #40

I skimmed through the synopsis but this philosophical statement baffles me (although obviously it is unrelated to the validity or invalidity of the proof): "The implications of [P ?= NP] on the general philosophical question of [..] whether human creativity can be automated, would be profound." How so? If P!=NP, that is obeyed by the brain as much as by computers and whatever trick our brains does to be creative desp…

How so? If P!=NP, that is obeyed by the brain as much as by computers and whatever trick our brains does to be creative despite of this, will be available to computers as well, regardless of P?=NP. What am I missing?

Let's talk math: In some very formal, reductionist sense, what we're doing when we do math is to start with a set of axioms, operate on them using a fairly small set of logical rules, and arrive at theorems that seem interesting.

If we do this very carefully -- much more carefully than a human would ever normally do, showing 100% of our work -- it's trivial to check such a proof automatically. You just look at each step, and verify that that step follows from the axioms + logical rules you're using + previous steps. This checking is clearly (handwave) polynomial: at worst, at each step N, you have to examine every axiom, every logical rule, and each prior step to make sure that step N+1 is legal.

So proof checking is in P.

Let's say I have a set of axioms, and a logic, and I want to know whether a theorem T is true given that system. One strategy I could use is to decide to only consider proofs of length less than N, and generate every legal theorem that I can reach in fewer than N logical steps. When I'm done, I check my list of proven theorems and see if any of them match T. Since I can always my answer in polynomial time, I know this is in NP.

The try-everything-possible algorithm has the downside of being a bit exponential (since we expect N to be very (very!) large for any interesting theorem) and so also a bit useless.

But what if a P=NP proof can provide guidance on how we should combine our axioms in order to reach theorem T? We suddenly have not a proof-checker, but a proof-generator! Anything that we can state in a formal language, we can simply ask the prover to prove -- it will either give a proof, or say that a proof of size That wouldn't be a disproof, and it's a Goedel/halting problem kind of argument that we may never really know how large N needs to be.)

Finding new proofs is a large part of what's considered creative in mathematics. It's hard to over-state how math might change with a tool like that available. The field has seen any number of revolutions before -- e.g., the effort of hundreds who worked on the algebraic roots of polynomials pretty much only survives in homework exercises nowadays -- but automating proofs would be Big.

(Finding interesting conjectures is valuable, too, but I doubt Erdos would be nearly as famous if he'd only posed his questions without his resume of theorems behind them.)

Re: P ≠ NP

#156

Several points on the question of whether the proof is likely to be correct: * As far as I know this paper wasn't circulated for informal peer review before being made public; I heard no talk on the grapevine. (Edit: apparently it was circulated and someone other than the author made it public.) * Therefore a proper assessment is going to take a while. Until then we can only speculate :-) * While the crank attempts a…

  * If the statistical physics method used here is powerful
  enough to resolve P != NP, then there's a good chance it
  is powerful enough to have led to many smaller results
  before the author was able to nail the big one. It's a
  little weird we haven't heard anything about that earlier.
Well, Wiles didn't publish intermediate results either, partly because someone might have beat him to the final result with those intermediate results. It would also give away what he was working on. Deolalikar was aiming for the grand prize as well, so skipping the publishing of intermediate results doesn't seem strange to me.

Re: P ≠ NP

#159
post #45

Earlier quoted context omitted.

If this proof is up for review, that would mean there could be errors in it, right?

As another commenter mentioned, it will likely take months or even years to verify.

At 66 pages, coming from a well regarding researcher, and with its professional style of writing, I'd be shocked if this wasn't reviewed and slotted for publication before the end of the year.

In fact, one may argue that by FOCS we'll have had so many graduate students, reading groups, and reviewers pour over this paper that we'll have either a consensus or have found an error.

Re: P ≠ NP

#160
post #53
post #40

I skimmed through the synopsis but this philosophical statement baffles me (although obviously it is unrelated to the validity or invalidity of the proof): "The implications of [P ?= NP] on the general philosophical question of [..] whether human creativity can be automated, would be profound." How so? If P!=NP, that is obeyed by the brain as much as by computers and whatever trick our brains does to be creative desp…

You must read it in context. What it says is that if P == NP then the implications are profound for applications such as cryptography and on the general question of whether human creativity can be automated. You can see why P == NP would have profound implications for crypto: many of our widely used techniques would turn out to, um, be easy to crack. I believe the intent regarding human creativity is that humans ofte…

Polynomial doesn't mean "easy".

O(n^10000) is polynomial but really not easy.

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