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Comment Scott Aaronson says it's garbage (Score 2) 199

Dear Slashdot editors, when it comes to science you don't understand, please don't publish anything that did not go through the peer review process. Especially when it comes to important, hard topics such as P != NP. At least in 99% of such cases, you are just creating empty sensations and helping spread bad science.

As for this particular paper, here is what Scott Aaronson thinks about it (repost from his blog at ):

At several people’s request, I’ve now taken a look at [the paper] and I can confirm that it’s complete garbage. The author is simply mistaken that solving the Schrödinger equation is “NP-complete” in any interesting sense: his argument for that seems to rely on a rediscovery of the adiabatic algorithm, but he doesn’t mention that the spectral gap could be exponentially small (and hence the annealing time could be exponentially large)—the central problem that’s been the bane of Farhi and his collaborators (and, of course, of D-Wave) for the past 15 years.

Also, even if you thought (for totally mistaken reasons) that quantum mechanics let you solve NP-complete problems in polynomial time, that might (or might not) suggest to you that quantum mechanics should be replaced by something else. But until you’d actually found a replacement, and given some sort of evidence for its truth, I don’t see how you could claim to have “solved the measurement problem”!!

As additional problems, the author appears to conflate the P vs. NP problem with the question of whether NP-complete problems can be efficiently solved in the physical world, a common novice mistake. And also, he seems comically unaware of everything that’s been done in quantum computing theory over the past 20 years about the issues he’s writing about—as if he just emerged from a cave.

Comment Re:How is that legal? (Score 1) 490

Sarcasm tags? Sure, we have their equivalents. For example, in this case one can use quotes. Feel the difference between the following two sentences?

I can't wait to do it.

I "can't wait" to do it.

I'm not buying your sarcasm theory. A reporter should know how to convey his intended meaning only. (Also, IMHO Grunwald's follow-up tweet makes it clear he is *not* an Assange supporter.)

Comment Re:Seems legitimate. (Score 1) 115

What you may be missing is the fact that this is a case of a pot calling the kettle black -- Zynga is notorious for being the opposite party in such cases. If you re-read the discussion with this in mind, I guess you'll find that many of the posts actually say "I hate Zynga's business strategy".

Comment Re:Security (Score 4, Informative) 271

Yes, FFT may be used in cryptography. But this is unrelated, as the first post in this thread talks about security. FFT has no connection to the security of cryptosystems.

As far as I'm aware, the security of *absolutely no* cryptosystem used in practice depends in any way on the FFT.

Yes, FFT gives us a way to multiply big integers quickly. But all cryptosystems that use big integers already *do* assume that everyone *can* multiply big integers quickly. Even if there was a ten-times speedup, this would mean absolutely no danger to their security.

(And one final nitpick: FFT is not the fastest way to multiply 4096-bit integers, those are still considered fairly short and you would probably gain a better performance out of some simpler-but-asymptotically-slower algorithm.)

Comment Why is this on Ask Slashdot? (Score 4, Insightful) 607

Why is this on Ask Slashdot? The question does not contain *any* indication that SyFy actually considers this, so at the moment it's just one person's speculation, nothing more. And anyway, (almost?) nobody here has the data or experience to make a qualified answer to the question in the post title.

Ask Slashdot should IMHO be limited to questions where our collective *experience* can actually help.

Comment Re:Wow --- volume 4BXz? (Score 1) 173

Wrong. The new version number will be larger than the previous one, obviously, by 5e-8. And even if you read the number as 3.integer, the new integer has one more digit than the old one. Why do you think it should be lower?

By the way, TeX version numbers are converging to pi, and Metafont version numbers are converging to e. This is intentional. Rumor has it that this should show how TeX and Metafont converge to perfection.

Comment bigram means two characters (Score 1) 117

I wish people would stop using the words "bigram" and "trigram" incorrectly. The "-gram" suffix comes from a Greek word for "a written character", the same root is in the word "grapheme". Hence bigram == a two-character substring, and trigram == a three-character substring. And these words are actually being used in the correct sense as well. Two-word and three-word substrings should IMHO be called "bilexes" and "trilexes", or something similar. But a good first step is to stop calling them bigrams and trigrams.

Submission + - 12th Internet Problem Solving Contest

misof writes: Roughly one thousand teams for all around the globe have already registered for IPSC 2010, which takes place on Sunday, June 6th. USD 3000 in prize money (courtesy of Facebook, Inc.) is waiting for the best few of them. Participation is free and the contest is open for everybody.

IPSC is what you could call "a programming contest with a twist". Over the years, the problems always push the boundary and go beyond the usual stuff you see in a programming contest.

For example, in past few years the contestants had to understand how arithmetics in computers differs from the one in mathematics, produce a sequence of cache requests that generates many page faults, solve a logic puzzle given as a flash game, or recognize images to evaluate a rock-paper-scissors game.

Comment Re:Working for Slashdot (Score 1) 338

Re your signature: because "am" stands for "ante meridiam", which means "before noon". So technically both "12am" and "12pm" are wrong, it is correct to use "midnight" and "noon" for those times.

Or use 24-hour clocks as we do, there the next hour is always (previous_hour + 1) modulo 24, which is much more pleasing to a programmer looking for patterns ;)

There, and now you have to look for a better sig :)

Comment Other: Flying like a pink elephant (Score 1) 1142

Seriously. The premise is false, the consequence can be anything we want and still our claim will be true.

There is no subject so important that *everyone* has to be forced to pass the "101 course" in it. If anything, most posters in this thread have a way too narrow definition of "everyone".

And even if we limit ourselves to "first world countries", the premise does not make much sense. Sure, the world would be a nicer place if everyone was able, say, to critically think for themselves -- but there's no way to make this happen, so why bother discussing such a hypothesis?

Comment Re:Misuse Of Statistics (Score 4, Informative) 120

Another misuse of statistics: Many people expect that FBI uses the DNA database in the following way:
1. get DNA sample from the crime scene
2. match DNA sample against all samples in the database
3. if you got a match, you got the killer.

This is not how it works. Say the real odds of a false positive are ten million to one. In a country of say 300 million people this still gives an expected 30 people who match the sample from the scene. Is each of them the criminal? Clearly not.

How it really works? Imagine that you already identified several suspects. If you take DNA samples of these few people and one of them matches the DNA from the hair from the scene, you can still conclude that given your knowledge, with a very high probability the person in question was present at the crime scene.

In other words, using DNA tests is perfectly reasonable as long as you know what you are doing, even if the probability of a false positive is several orders of magnitude larger than one to a billion.

Comment Re:I'm Slovak and the summary is wrong. (Score 1) 926

At least have the courtesy to:
  1. 1. read the post you are replying to
  2. 2. sign your post

when calling bullshit. I never claimed that the Slovak version is true and different from everyone else's. I said it is more or less equal to the BBC version. What *still* obviously does not match the news in either country is the Slashdot article.

Comment I'm Slovak and the summary is wrong. (Score 5, Informative) 926

I'm Slovak. The version presented in our press goes as follows. Planting and then detecting the explosives was a part of a dog training security exercise of the Slovak police. The exercise was a disaster. Out of the 8 items planted in the travellers' luggage only 7 were found successfully. These are probably the "seven stopped by airport security" from the summary. The seven do NOT include the guy in Dublin. That is the unlucky guy that got the eighth piece. His luggage passed all security checks and he unknowingly brought the piece of explosives with him into Dublin, where he was then detained by the Irish police. This more or less matches the BBC version linked from the summary, only the summary is wrong. Please update it.

Comment Re:Ridiculous (Score 1) 752

Most of all, the article is just plain wrong, especially in the last sentence "Their servers are only a tiny fraction of computers deployed world-wide that are interpreting PHP code." From what I've heard, Facebook does use PHP, but their PHP code is not interpreted, it is compiled using a custom compiler. And if you RTFA, it clearly states that Facebook developers implemented numerous optimizations that are not available in the default PHP distribution. There's no evidence that would support the "conservative ratio of 10 for the efficiency of C++ versus PHP code" in Facebook's case.

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Enzymes are things invented by biologists that explain things which otherwise require harder thinking. -- Jerome Lettvin