Mathblogging.orgRecent Postshttp://www.mathblogging.org/scripts/feed.php20150522T15:01:1504:00No copyright asserted over individual posts; see original posts for copyright and/or licensing.Mathblogging.org Atom serializerKansas redistributes money from the poor to the bankshttp://www.mathblogging.org/post/11962120150522T07:38:1104:00Cathy O'Neil, mathbabeTake a look at this article (hat tip Felix Salmon), which has me absolutely raging this morning, about new legislation in Kansas that prevents poor people on welfare from taking out more than $25 per day using their stateissued debit cards. To be clear, you have to round up to the nearest $20 if you want […]Extraescolares de matemáticas con Sangakoohttp://www.mathblogging.org/post/11962220150522T07:37:1204:00SangakooTenemos excelentes noticias que contaros. ¡Nuestro proyecto educativo se amplía con una nueva escuela! El próximo curso estaremos en Maristes Champagnat de Badalona. Y además, lo hacemos aplicando nuestra metodología como actividad extraescolar. La actividad está abierta a todo aquel que esté interesado en participar sea o no alumn@ de la escuela para secundaria. Lo cierto […]Nonsymmetric semidefinite optimization problems.http://www.mathblogging.org/post/11961820150522T07:33:0004:00Erling D. AndersenIn semidefinite optimization we optimize over a matrix variable that must be symmetric and positive semidefinite.<br />Assume we want to relax the assumption about symmetry. Is that an important generalization? The answer is no for the following reason. Since <br /> (X+X')/2 is PSD<br />implies<br /> X <br />is PSD. Observe<br /> X = (X+X')/2+(XX')/2<br />and<br /> y'( (XX')/2) y >= 0.<br />implying X is PSD.<br />Note (XX')'=(XX') implying XX' is skew symmetric.<br />Hence, any
[…][DMANET] MISTA 2015: Call for Participationhttp://www.mathblogging.org/post/11962420150522T07:32:0004:00Lance Fortnow
<br>MISTA 2015: Call for Participation
<br>Multidisciplinary International Scheduling Conference: Theory & Applications
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<br>2528 August 2015,
<br>Prague, Czech Republic
<br>http://www.schedulingconference.org/
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<br>MISTA 2015 is the seventh in the conference series. Previous conferences
<br>were run in Ghent (2013), Arizona (2011), Dublin (2009), Paris (2007), New
<br>York (2005) and Nottingham (2003). This year the conference takes</br>
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[…]What’s do you see that is similar / differenthttp://www.mathblogging.org/post/11961920150522T07:30:2204:00mjlawlerTraveling this morning, but would have loved to have been able to ask the boys some notice / wonder and same / different questions about these two things this morning: First Dan Anderson’s amazing geometry video / program: Second, the famous bowling ball pendulum:[DMANET] ANOR Special Issue  Applications of Operations Research for Neurosciencehttp://www.mathblogging.org/post/11962520150522T07:25:0004:00Lance FortnowDear Colleagues,
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<br>the Special Volume "Applications of Operations Research for
<br>Neuroscience" of the journal "Annals of Operations Research" welcomes
<br>for submission excellent contributions to the subject.
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<br>Please find the call for papers under
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<br>http://rutcor.rutgers.edu/CfP_Annals_of_Operations_Research.pdf.
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<br>Kind regards,
<br>GerhardWilhelm Weber
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[…]Groups and Group Actions: Lecture 16http://www.mathblogging.org/post/11961620150522T07:02:0304:00theoremoftheweekIn which we meet Cayley’s Theorem and reach the end of this particular adventure, but catch a glimpse of faroff lands still to be explored. Theorem 68: Let be a group, let be a set. Given a left action of on , there is an associated homomorphism . Given a homomorphism , there is an associated […]Mathematics can only be understood backwards but it must be proved forwardhttp://www.mathblogging.org/post/11961720150522T06:27:0004:00Mark“Life can only be understood backwards; but it must be lived forwards.”<br />― Søren Kierkegaard<br /><br />++++<br /><br />Lots of students have observed that they didn't really understand a subject until they<br /><br />_____<br /><br /><br />algebra calculus<br /><br /><br />++++++++++++++<br /><br />We need A to prove B but we need B to understand the why of A.<br /><br />+++++++++++++<br /><br />On the first pass, jettison all of the inessentials from AHow far Frodo and Sam walked compared to real geographyhttp://www.mathblogging.org/post/11961520150522T06:21:2204:00Nathan YauIf you read the books or watched the movies, you get the sense that Frodo and Sam walked pretty far to toss that ring in the fire. Imgur user mattsawizard…Tags: humor, Lord of the RingsChoongbum Lee proved the BurrErdős conjecturehttp://www.mathblogging.org/post/11961320150522T05:45:0804:00Gil KalaiLet be a graph. The Ramsey number is the smallest such that whenever you color the edges of the complete graph with vertices with two colors blue and red, you can either find a blue copy or a red copy of . Ramsey’s famous theorem asserts that if is a complete graph on vertices then […]Outer space: You guessed ithttp://www.mathblogging.org/post/11961420150522T05:28:5704:00mf344
John D. Barrow
If you are a flower then April is allegedly the cruellest month, but if you are a student of any sort then I'm sure you would have picked June.
If you are a flower then April is allegedly the cruellest month, but if you are a student of any sort then I'm sure you would have picked June. June is a month of
[…]Reaction Time & Web Data Collectionhttp://www.mathblogging.org/post/11961220150522T04:02:5504:00Evan WeinbergIf you put out an open call through email to complete a task for nothing in return, it might make sense not to expect much. I tried to make it as simple as possible to gather some reaction time data … Continue reading →MATLAB: Vectorisation is a doubleedged swordhttp://www.mathblogging.org/post/11961020150522T04:01:2004:00Mike CroucherImagine that you are a very new MATLAB programmer and you have to create an N x N matrix called A where A(i,j) = i+j Your first attempt at a solution might look like this N=2000 % Generate a NbyN matrix where A(i,j) = i + j; for ii = 1:N for jj = 1:N [...]Facing the facts  Wittgenstein as a Kantian? (guest post)http://www.mathblogging.org/post/11961120150522T03:52:1804:00Catarina Dutilh NovaesFor my MA course on Wittgenstein earlier this year, students had to write a short essay, blog poststyle, on the Tractatus. One of them, Joseph Wilcox, took up the challenge of asking what exactly it means to say that Wittgenstein's project in the Tractatus is essentially a Kantian project ...http://www.mathblogging.org/post/11960820150522T03:30:0004:00David5/22/2015<br /><br />"This statement is false."<br /><br /><br /><br />DavidMore Birthdayshttp://www.mathblogging.org/post/11960920150522T03:30:0004:00David<br /> <br />5/22/2015<br />Mathematicians born on this day:1848 : Hermann Schubert1865 : Alfred Dixo
[…]Rise of data arthttp://www.mathblogging.org/post/11960720150522T03:01:3904:00Nathan YauData art is on the rise. Jacoba Urist for the Atlantic gets into the beginnings and its current prevalence.
Art is a constant march of expansion, according to Harvey Molotch,…Tags: Atlantic, riseSur une (petite) erreur d'Isaac Newtonhttp://www.mathblogging.org/post/11960420150522T01:00:0004:00François GuéritaudCalculer la forme de la Terre, aux temps héroïques.

L'IHP, maison d'histoires
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Piste rouge,
featuredThree and Fourhttp://www.mathblogging.org/post/11960520150522T01:00:0004:00(x, why?)(Click on the comic if you can't see the full image.)<br /> (C)Copyright 2015, C. Burke.My other choice: Every Kirk has his Gorn . . . The more I think about it, I might've gotten enough scifi references to fill that in, had I tried, had I tried ... Damn it, Jim! Meanwhile, 80s Week continues. <BR><BR><BR><BR><BR>Come back often for more funny math and geeky comics.<br><br><br></br>
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Four million page views: a million here, a million there and soon enough we're talking real readership...http://www.mathblogging.org/post/11960620150522T01:00:0004:00Igor Some Long Distance Blogging with about a million page views per year. Here are the historical figures:<br /> May 21, 2015, 4 million page viewsDecember 2, 2014, 3.5 million page viewsJune 7, 2014 3 million page viewsNovember 07, 2013, 2.5 million page viewsMay 27, 2013 2 million page views October 25, 2012, 1.5 million page viewsa page view is not the same as a unique visit, here is that figure: <br /><br /> which amoints to 650 unique visits per day on average.Here as some interesting tags
[…]Maintaining Sanity, Reviewing Prioritieshttp://www.mathblogging.org/post/11960220150521T22:25:2104:00Evan WeinbergI've had a really busy year. I've always said at the start of the school year that I'm going to say 'no' more frequently in as politely a way as possible. I've said I'd be more honest about priorities. Instead … Continue reading →Mai 2015, 4ème défihttp://www.mathblogging.org/post/11960120150521T22:00:0004:00Ana RechtmanPour la deuxième année, chaque semaine, un défi du calendrier mathématique...

Défis du Calendrier Mathématique Reflecting on Mathematicshttp://www.mathblogging.org/post/11960020150521T21:42:0404:00dkane47I spent the last two days in class reflecting on mathematics with my students. Here’ the context: This week is state testing week. I only taught class two days, between testing days and field day Friday. I didn’t want to stress kids out while they were taking tests, but also wanted to be purposeful with […]asearchforbeauty:
Torus Knothttp://www.mathblogging.org/post/11959820150521T21:30:4504:00Unknown<br/><br/>asearchforbeauty:
Torus KnotListening Carefully to Student Thinkinghttp://www.mathblogging.org/post/11959720150521T20:09:0704:00mathmindsblogRecently, I have been reviewing a new “CCSSAligned” middle school curriculum and find myself completely frustrated with the overabundance of scaffolding and lack of student thinking required on every assignment. Not having the days/weeks it would take for teachers to engage in the mathematics as both learners and teachers, I needed a short, powerful way […]An Intentional and an Unintentional teaching experiment regarding proving the number of primes is infinite.http://www.mathblogging.org/post/11959620150521T19:58:4904:00Unknown<br />
I taught Discrete Math Honors this semester. Two of the days were cancelled entirely because of snow (the entire school was closed) and four more I couldn't make because of health issues (I'm fine now). People DID sub for me those two and DID do what I would have done. I covered some crypto which I had not done in the past.<br />
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Because of all of this I ended up not covering the proof that the primes were infinite until the last week.<br />
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INTENTIONAL EXPERIMENT: Rather than phrase it as a proof by […]Schooltoon: La Scuola A Cartoonhttp://www.mathblogging.org/post/11959520150521T19:47:0004:00annarita ruberto<br>Cosa è Schooltoon? Ve ne accennai l'anno scorso nel post "Le proporzioni...E Lo Scherzo A Ferrari", ma ho deciso di dedicare un post specifico a questo progetto interessante, che nel frattempo è cresciuto.<br><br>Riporto di seguito la presentazione che ne fa il sito dedicato al progetto:<br><br>"Schooltoon è una ‘scuola a cartoon’, nella quale il Prof. Eddie, Moretti, Giovanna e tanti altri personaggi rivoluzionano il modo di insegnare ed imparare, attraversando a suon di rock i
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[…]On This Day in Math  May 22http://www.mathblogging.org/post/11959920150521T19:00:0004:00Pat BallewThe Le Petit Journal cover, on 1912 April 21, shows eclipse watchers in 1912 along with the solar eclipse of May 22, 1724, the previous total solar eclipse visible from Paris, France<br /><br /><br />“Biographical history, as taught in our public schools, is still largely a history of boneheads:ridiculous kings and queens, paranoid political leaders, compulsive voyagers, ignorant generals  the flotsam and jetsam of historical currents. The men who radically altered history, the great scientists
[…]Bingo Lingohttp://www.mathblogging.org/post/11959420150521T18:43:0104:00Megan SchmidtThis time of year, the standards used to measure the success of a lesson may look different than they do at other times of the year. For example, some teachers might consider “Students not using worksheets to have paper airplane throwing contest” to consistute a lesson well executed. To a certain extent, I am joking, […]ICPC 2015 World Final Problem Dhttp://www.mathblogging.org/post/11959320150521T18:30:0704:00beni22sofThis is a solution to problem D from the International Collegiate Programming Contest. The list of the problems can be found here. This is one of the problems which was really appealing for me, from the start. The idea is the following: suppose you have a Swiss cheese cube of (the units are centimeters). This […]