MetaFilter posts tagged with math and internet

Math Overflow

escabeche — Sat, 17 Oct 2009 12:28:26 -0800

Math Overflow is the first attempt to use the Stack Exchange platform, already popular with programmers, as a scientific research tool. Founded this month by a group of young mathematicians, including Scott Morrison and Ben Webster of the Secret Blogging Seminar, the site is already wrestling with hundreds of questions, ranging from the technical ("When is a map given by a word surjective?") to the historical ("Most interesting mathematics mistake?")

Computable data* (conceivably knowable) about people

kliuless — Fri, 01 May 2009 06:42:19 -0800

Stephen Wolfram discusses Wolfram|Alpha: Computational Knowledge Engine - at the same time Google Adds Search to Public Data, viz: "Nobody really paid attention to the two hour snorecast" -- like a cross between designing for big data and a glossary of game theory terms -- on Wolfram|Alpha (previously), yet the veil is being lifted nonetheless: "[on] a platonic search engine, unearthing eternal truths that may never have been written down before," cf. hunch & cyc (and in other startup news...) [via] *boiling it down to that which can be computed (about the world)

Information doesn't want to be scale free

escabeche — Thu, 23 Apr 2009 22:48:33 -0800

"the scale-free network modeing paradigm is largely inconsistent with the engineered nature of the Internet..." For a decade it's been conventional wisdom that the Internet has a scale-free topology, in which the number of links emanating from a site obeys a power law. In other words, the Internet has a long tail; compared with a completely random network, its structure is dominated by a few very highly connected nodes, while the rest of the web consists of a gigantic list of sites attached to hardly anything. Among its other effects, this makes the web highly vulnerable to epidemics. The power law on the internet has inspired a vast array of research by computer scientists, mathematicians, and engineers. According to an article in this month's Notices of the American Math Society, it's all wrong. How could so many scientists make this kind of mistake? Statistician Cosma Shalizi explains how people see power laws when they aren't there: "Abusing linear regression makes the baby Gauss cry."

15 bits of crypto should be enough for anybody

finite — Fri, 16 May 2008 22:01:42 -0800

On May 13, security advisories published by Debian and Ubuntu revealed that, for over a year, their OpenSSL libraries have had a major flaw in their CSPRNG, which is used by key generation functions in many widely-used applications, which caused the "random" numbers produced to be extremely predictable. [lolcat summary] How bad is it? It's pretty bad. Understand that these keys are used not only for encryption, but also for authentication. The keyspace has been reduced to a mere 32,768 possibilities, and you can already download them all, along with tools to use them. Worse still, in the days before the issue became publicly known, there was a noticeable spike in the number of brute-force attacks on SSH servers, indicating that there has already been significant exploitation of this vulnerability. Partial timeline of events: In May 2006, a bug led to a question which led to the fateful patch being applied to md_rand.c (in Debian's "unstable" development branch). In April 2007, Debian 4.0 "etch" and Ubuntu 7.04 were both released, which was the beginning of the inclusion of the buggy version of OpenSSL in officially-released distributions. The bug remained unfixed through the releases of Ubuntu 7.10 and 8.04. On May 7, 2008, the patch to fix the problem was committed to Debian's source repository, and on May 13 the issue was officially disclosed and updated packages were made available to users. (The patch's availability days before public disclosure of the bug appears to be a violation of Debian's policy.) Here are some responses from Debian blogs, and two from an OpenSSL developer.

.99999...=1

escabeche — Sun, 30 Sep 2007 06:55:52 -0800

No, I'm sorry, it does. There are some arguments that never end. John or Paul? "Another thing coming" or "Another think coming?" But none has the staying power of "Is 0.999999...., with the 9s repeating forever, equal to 1?" A high school math teacher takes on all doubters. Round 2. Round 3. Refutations of some popular "They're not equal" arguments. Refutations, round 2. You don't have to a mathematician to get in on the fun: .99999=1 discussed on a conspiracy theory website, an Ayn Rand website (where it is accused to violating the "law of identity"), and a World of Warcraft forum. But never, as far as I can tell, on MetaFilter.