Mathblogging.orgRecent Postshttp://www.mathblogging.org/scripts/feed.php20141126T02:28:0305:00No copyright asserted over individual posts; see original posts for copyright and/or licensing.Mathblogging.org Atom serializerMore on Big Datahttp://www.mathblogging.org/post/10498820141124T07:28:0005:00Francis DieboldAn earlier post, "Big Data the Big Hassle," waxed negative. So let me now give credit where credit is due.<br /><br />What's true in timeseries econometrics is that it's very hard to list the thirdmostimportant, or even secondmostimportant, contribution of Big Data. To a good approximation, there aren't any. Which makes all the more remarkable the mindboggling  I mean completely offthecharts  success of the firstmostimportant contribution: volatility estimation from highfrequency […]Pvalues and power in statistical testshttp://www.mathblogging.org/post/10498720141124T07:18:2805:00Cathy O'Neil, mathbabeToday I’m going to do my best to explain Andrew Gelman’s recent intriguing post on his blog for the sake of nonstatisticians including myself (hat tip Catalina Bertani). If you are a statistician, and especially if you are Andrew Gelman, please do correct me if I get anything wrong. Here’s his post, which more or […]English versus Chinese color descriptorshttp://www.mathblogging.org/post/10498420141124T05:44:4605:00Nathan YauColor exists on a continuous spectrum, but we bin them with names and descriptions that reflect perception and sometimes culture. …Tags: color, language, WikipediaWhat is a proof, really?http://www.mathblogging.org/post/10498520141124T05:35:1505:00Keith DevlinWhat is a mathematical proof? Way back when I was a college freshman, I could give you a precise answer: A proof of a statement S is a finite sequence of assertions S(1), S(2), … S(n) such that S(n) = S and each S(i) is either an axiom or else follows from one or more […]AutoRun McMyAdmin at reboot/start (Linux/Ubuntu)http://www.mathblogging.org/post/10497920141124T05:25:2105:00lttt(小小泪)1. Login as root, create a file as vim /etc/init.d/McMy […]Helicobacter pylori and stem cells in the gastric crypthttp://www.mathblogging.org/post/10498120141124T05:15:0005:00Artem KaznatcheevLast Friday, the 4th Integrated Mathematical Oncology Workshop finished here at Moffitt. The event drew a variety of internal and external participants — you can see a blurry photo of many of them above — and was structured as a competition between four teams specializing in four different domains: Microbiome, Hepatitis C, Human papillomavirus, and […]Buffett on inflation and return on equityhttp://www.mathblogging.org/post/10498320141124T05:10:3505:00EditorsWarren Buffett demolishes the then conventional wisdom that stocks should perform well during periods of high inflation using simple but penetrating analysis. It is no longer a secret that stocks, like bonds, do poorly in an inflationary environment. We have … Continue reading →Proving a nice patternhttp://www.mathblogging.org/post/10497820141124T05:00:0005:00ColinOver on reddit, noncognitivism posted a nice sequence s/he had come across: $4 + 1 = 5 = \sqrt{ (1)(2)(3)(4) + 1 }$ $(4+6) + 1 = 11 = \sqrt{ (2)(3)(4)(5) + 1}$ $(4+6+8) + 1 = 19 = \sqrt{ (3)(4)(5)(6) + 1}$ $…$ $(4+6+ … + (2k+2)) + 1 = \sqrt{ k(k+1)(k+2)(k+3) + 1 }$ Lovely. But why? Well, the left hand side is an arithmetic series (with one added on) – in Core 1 terms, $a = 4$ and $d=2$, so its sum is $\frac{k}{2}\left[ 2(4) + (k1)(2) \right] = \frac{k}{2} \left[ 8 + 2(k1)\right] =
[…]Mol language and chemlambda gui instead of html and web browsers gives new Net service?http://www.mathblogging.org/post/10498020141124T04:54:4205:00chorasimilarityThe WWW is an Internet system, based on the following ingredients: web pages (written in html) a (web) browser a web server (because of the choice of clientserver architecture) Tim BernersLee wrote those programs. Then the WWW appeared and exploded. The force behind this explosion comes from the separation of the system into independent parts. … Continue reading Mol language and chemlambda gui instead of html and web browsers gives new Net service? →PreThanksgiving Day activitieshttp://www.mathblogging.org/post/10498220141124T04:53:3405:00LeslieWe have a number of great activities for this time of year. Delicious pumpkin pie – Estimation, proportional reasoning, fraction multiplication, delicious pie Macy’s Thanksgiving Day parade – Describe, measure, calculate marching time, volumes of the giant balloons Not enough mashed potatoes –…Read more →Encuentra todas las funcioneshttp://www.mathblogging.org/post/10497720141124T04:30:2805:00^DiAmOnD^Vamos con el problema semanal. Ahí va: Encuentra todas las funciones que cumplen las dos condiciones siguientes: , para todo . cuando . Que se os dé bien. Entra en Gaussianos si quieres hacer algún comentario sobre este artículo, consultar entradas anteriores o enviarnos un mensaje.Construye tú también el poliedro de Császár.Entra en Gaussianos si quieres hacer algún comentario sobre este artículo, consultar entradas anteriores o enviarnos un
[…]Un reto tricolorhttp://www.mathblogging.org/post/10497520141124T03:33:1605:00cifrasyteclasNo te mates, que no hay manera le decían los otros dos alumnos a su compañero. Habían venido a resolver unas dudas y, cuando ya se iban, uno preguntó cuándo aparecería otro reto en el blog. Es que tengo un amigo al que siempre se los cuento, dijo. No me pude resistir. Y ahí seguía, un buen rato después, intentando evitar triángulos tricolores.
(Sigue leyendo...)La magia de la tabla Periódica [Tito Eliatron Dixit]http://www.mathblogging.org/post/10497620141124T03:15:2605:00eliatronMi primera aportación a CarnaMat58 es este anuncio de conferencia:
La magia de la Tabla Periódica [Conferencia]1792http://www.mathblogging.org/post/10497420141124T03:00:0005:00Mathematical Association of America1792 = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 7.<br /><br />1792 is a Friedman number (A036057).<br /><br />1792 is the maximum number of pieces obtained by slicing a bagel (torus) with 21 cuts (A003600).<br /><br />1792 is a composite number such that the square root of the sum of squares of its prime factors is an integer (A134605).<br /><br />1792 is the number of simple graphs with 9 vertices and two cycles (A112410).<br /><br />1792 divides 978  1.<br /><br /><br />Source: OEISVisualizing Quaternions with Unityhttp://www.mathblogging.org/post/10497320141124T02:53:2305:00luckytoiletHow do you model the position and orientation of an airplane? Position is easy, just represent it with a point in 3D space. But how do you specify its orientation — which direction it’s pointing? At first glance, it seems a vector will do. After all, a vector points in some direction, right? If the […]La magia de la Tabla Periódica [Conferencia]http://www.mathblogging.org/post/10497220141124T02:30:0005:00UnknownMiquel DuránFernando Blasco¿Es posible aprender ciencia mientras se hace magia? ¿Es posible que en una conferencia científica tengan cabida trucos de Magia? ¿Pueden un químico y un matemático dar una charla al alimón? Está claro que no siempre. Pero si se junta gente como Miquel Durán y Fernando Blasco, eso y mucho más es posible. <br /><br />Pues esto es lo que va a ocurrir el próximo jueves. Como parte del Programa de Actividades de la de la Facultad de Matemáticas de la Universidad de
[…]Il problema dello scambiohttp://www.mathblogging.org/post/10497120141124T01:00:2405:00Rudy d’Alembert, Alice Riddle e Piotr Rezierovic SilverbrahmsRalph Waldo Emerson diceva che “Scovare i piccoli errori è la gioia delle piccole menti”. Bene, abbiamo trovato un altro problema che Ghersi ha copiato da qualcun altro (Loyd, chiaro: è lui il “tema” di quest’anno). E siccome lo conoscete, ci prendiamo qualche libertà sarcastica.
Questo è un problema classico per i ferrovieri, presentato per mostrare [...]Rome (ou pas ?), 1939http://www.mathblogging.org/post/10496820141124T01:00:0005:00Michèle AudinUn Congrès excluant les mathématiciens juifs et comment réagir à cette situation ?

Mathématiques ailleurs
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Piste verte,
featuredRandomized Interpolative Decomposition of Separated Representationshttp://www.mathblogging.org/post/10496920141124T01:00:0005:00IgorRandom projections with tensors.<br /><br /><br />Randomized Interpolative Decomposition of Separated Representations by David J. Biagioni, Daniel Beylkin, Gregory Beylkin<br />We introduce tensor Interpolative Decomposition (tensor ID) for the reduction of the separation rank of Canonical Tensor Decompositions (CTDs). Tensor ID selects, for a userdefined accuracy \epsilon, a near optimal subset of terms of a CTD to represent the remaining terms via a linear combination of the selected terms. Tensor ID can be used as
[…]The Modular Forms Database is Annoyinghttp://www.mathblogging.org/post/10497020141124T00:57:0505:00galoisrepresentationsIt used to be the case, 10 or so years ago, that William Stein maintained a website with extensive tables of expansions of modular forms, computed using magma. However, as the edifice of civilization begins to crumble, this website no … Continue reading →Guest Post about Barbie `I can be an engineer'  Sounds good but its not.http://www.mathblogging.org/post/10496720141123T23:08:5105:00Unknown<br />
There is now a I can be an engineer Barbie. That sounds good! It's not. Imagine how this could be turned around and made sexist. What you are imagining might not be as bad as the reality. Depends on your imagination.<br />
<br />
Guest Blogger Brittany Terese Fasy explains:<br />
<br />
Remember the controversy over the Barbie doll that said<br />
"Math class is tough!"? Well, Barbie strikes again.<br />
<br />
If you haven't heard about II can be a computer engineer it is a story about how Barbie, as a "computer engineer" […]NaBloPoMo #16 and #MTBoSChallenge Weekly Summary15http://www.mathblogging.org/post/10496620141123T22:28:0005:00Beth FergusonWe finally made it to Thanksgiving Break. <br />This year we get a whole week!<br />It's amazing. <br />It's our first day off since Labor Day ... and it feels good!<br /><br />Big events this week ...<br /><br />Started decorating for Christmas yesterday ... put up the tree,Shopped for stocking stuffers yesterday at Target.Relaxed today at the movies ... Whiplash ... it was excellent.Get to catch up on laundry tomorrow AND reading!Twitter Chats ... #Alg2Chat on Monday & #Eduread on WednesdayFlying to Tennessee to see family this
[…]A Challenging Math Problem From “Little Man Tate” (1991)http://www.mathblogging.org/post/10496420141123T22:00:3605:00Presh TalwalkarThis week’s puzzle comes from the 1991 film Little Man Tate. Here is how the film presents the problem. How about giving me a number that when divided by the product of its digits the quotient is 3. And if you were to add 18 to this number the digits would be inverted. In the […]A Free Slope Puzzle!http://www.mathblogging.org/post/10496520141123T21:52:4405:00Shana Donohue If you teach slope and are looking for a fun activity to help in the days leading up to Thanksgiving, I’d love for you to try my new slope puzzle. You can find it in the “Today’s Flash Freebie!” box over there on the sidebar of my blog or the Freebies! tab on my […]St Andrews to Banffhttp://www.mathblogging.org/post/10496320141123T21:07:5605:00Peter CameronNo, not 120 miles north, but several thousand miles west to Banff, Canada, home of the Banff International Research Station for Mathematical Innovation and Discovery. I travelled south from St Andrews to London yesterday. We went first class; the cost … Continue reading →Conquering the Hundred Charthttp://www.mathblogging.org/post/10496220141123T20:49:0005:00Donna BoucherMathematics is all about patterns. Some describe mathematics as the science of patterns, and the ability to understand patterns is described as a key concept in NCTM's algebra standard. <br /><br />I didn't like math growing up. Now, it fascinates me almost to the point of obsession, and I attribute that to two things: (1) I now understand the math behind the procedures I was taught, and (2) I see the patterns that were never pointed out to me before.<br /><br />Since I love patterns, it should be no surprise […]254A, Notes 1: Elementary multiplicative number theoryhttp://www.mathblogging.org/post/10496120141123T19:51:3705:00Terence TaoIn analytic number theory, an arithmetic function is simply a function from the natural numbers to the real or complex numbers. (One occasionally also considers arithmetic functions taking values in more general rings than or , as in this previous blog post, but we will restrict attention here to the classical situation of real or […][DMANET] Invitation for: [IEEE] Computing Technology and Information Management Conference [ICCTIM2015], Malaysiahttp://www.mathblogging.org/post/10498620141123T19:39:0005:00Lance Fortnow***************************************************************************
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[…]On This Day in Mathematics  November 24http://www.mathblogging.org/post/10496020141123T19:00:0005:00Pat Ballew<br />Albertus Magnus<br />To call in the statistician after the experiment is done may be no more than asking hm to perform a postmortem examination: he may be able to say what the experiment died of.<br />~Fisher, Ronald Aylmer<br /><br />The 328th day of the year; 328 is the sum of the first fifteen primes, and is a taunumber since it is divisible by the number of divisors it has. <br /><br /><br />EVENTS1639 British astronomers Jeremiah Horrocks and William Crabtree became the first observers to record a transit of Venus. Horrocks was […]Kuperberg’s parablehttp://www.mathblogging.org/post/10495920141123T18:34:2405:00ScottRecently, longtime friendoftheblog Greg Kuperberg wrote a Facebook post that, with Greg’s kind permission, I’m sharing here. A parable about pseudoskepticism in response to climate science, and science in general. Doctor: You ought to stop smoking, among other reasons because smoking causes lung cancer. Patient: Are you sure? I like to smoke. It also creates jobs. […]