Posts
July 03, 2015
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12:18 PM  “UK outmoded universities must modernise”
[A rather stinky piece in The Guardian today, written by a consultant selfstyled Higher Education expert… No further comments needed!] “The reasons cited for this laggardly response [to innovations] will be familiar to any observer of the university system: an inherently conservative and riskaverse culture in most institutions; sclerotic systems and processes designed for a […]
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12:15 PM  The annoying boxes puzzle: solution
I presented this logic puzzle on Wednesday:
There are two boxes on a table, one red and one green. One contains a
treasure. The red box is labelled "exactly one of the labels is
true". The green box is labelled "the treasure is in this box."
Can you figure out which box contains the treasure?
It's not too late to try to solve this before reading on. If you
want, you can submit your answer here:
The treasure is in the red box
The treasure is in the green box
There is not enough
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11:46 AM  Signed incidence matrices in Sagemath
Let be a graph with an edge orientation. This means that we are given , where V is the set of vertices and E a set of ordered pairs of distinct vertices representing the edges, and, for each edge an “orientation”. Simply put, an orientation on $\latex \Gamma$ is a list of length E consisting […]
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11:39 AM  Serveurs SVN
Subversion (SVN) est un outil informatique qui permet de gérer la collaboration sur des documents et en particulier des textes. Il automatise (jusqu’à un certain point!) la mise en commun des modifications et systématise l’archivage. Son utilisation nécessite un logiciel sur la machine de chaque collègue (“client svn”) mais aussi un logiciel (“serveur svn”) tournant […]
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11:19 AM  What kind of happiness should we strive for?
Some of you may have stumbled across the New York Times’ recent Room For Debate, addressing the pursuit of happiness. Short and insufficient summary: William Davies: Once you focus on optimizing happiness, you will be asking for trouble. At the individual level, optimizing for happiness will be used against us at work. At a higher level, […]
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11:19 AM  Catch A Few "Rays" for July 4th
Not going to add much to the diagram above but STEM is all about APPLYING math and science, yes?OK, so the expression for the angle labeled y is y=90x!The graphic isn't great so I hope you can read that angle! I left the diagram as openended as possible so students and educators can make conjectures and "assumptions". Feel free to comments or send me a direct email via the Blogger Contact Form. HAPPY FOURTH!VISIT ME DAILY ON TWITTER AT twitter.com/dmarain
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11:19 AM  Math Bits of the Week
Here and there:
1) First, a fun little (economics) paradox over at MathFrolic this morning:
http://mathfrolic.blogspot.com/2015/07/gladlypaying110fordollarbill.html
2) Conway.... JJJohn Conway!:
ICYMI, last Monday I got to talk with Siobhan Roberts about her upcoming biography of John Conway:
http://mathtango.blogspot.com/2015/06/siobhanrobertsplayingwithgeniuses.html
...and
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Welcome to Season 3 of Geometry Daily! I will continue what I did in 2012 (Season 1) and 2013 (Season 2): Creating a new minimal geometric composition each day.Oh wow, that was some time ago since the last post. I did a lot of collaborations, prints, shirts, etc. Also, I settled in my new job at the university and had some serious family time. Now it’s time to do what I love and it’s more fun than ever!The rules do not change: square format, one clear idea, simulated print of no more than
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10:43 AM  Don’t let the maps fool you
Maps are fun to look at and get easier to make every day, so there's a lot of them floating around in the world. But before you sit down to…Tags: data literacy
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This is an excerpt from friend of The Aperiodical, Matt Parker’s book, “Things to Make and Do in the Fourth Dimension”, which is out now in paperback. There’s a lovely function in mathematics called the factorial function, which involves multiplying the input number by every number smaller than it. For example: $\operatorname{factorial}(5) = 5 \times 4 \times 3... Read more »
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[Apologies for possible crossposting]CALL FOR PAPERSElsevier  Pervasive and Mobile ComputingSpecial Issue onPervasive Social Computinghttp://www.journals.elsevier.com/pervasiveandmobilecomputing/callforpapers/Submission Deadline: 30 November 2015Pervasive Social Computing represents a new paradigm resulting fromthe convergence of Pervasive Mobile Computing with Social Networking;it aims to take advantage of human social relationships to enable theattainment of users' tasks in
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8:45 AM  Article published by PRL
Our article “Visualizing Pure Quantum Turbulence in Superfluid He3: Andreev Reflection and its Spectral Properties” has been published by PRL and features as an editors selection: http://journals.aps.org/prl/ http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.015302
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8:34 AM  Impossible Cheese Stick
Impossible Cheese Stick
by Nathan Bruning
http://impossible.info/english/art/computer/nathanbruning.html
Author  https://dribbble.com/yeahsocreative
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7:31 AM  Websheets
Next week I am headed to the ITiCSE conference (Innovation and Technology in Computer Science Education), in Vilnius, Lithuania, to present Websheets, an exercise system for programming problems in C++ and Java. Websheets combines a couple of ideas. It is an online system where students get immediate feedback on their programming solutions. This has become very common […]
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5:11 AM  Barbie Zip Line (2015) Part 1
Last summer I tried Barbie Zip Line and reported the experience here. I also supported a handful of Math 8 teachers interested in Barbie Zip Line during the school when they explored the Pythagorean Theorem. I have to admit, with every experience, it always felt like it could be different, possibly better. This year, I went a different route and Part 1 just documents what I've done so far. Part 2 will be the conclusion.First, I avoided the Pythagorean Theorem (for now). On Monday, my […]
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4:24 AM  Have Kids? Missing Math?
In just a few short weeks my kids and I will be partaking in this water obstacle course on Lake Siskiyou in Northern California. After several tentative years in the water, my 6yearold recently learned to swim and now I … Continue reading →
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Professor Larry Laudan Lecturer in Law and Philosophy University of Texas at Austin “When the ‘NotGuilty’ Falsely Pass for Innocent” by Larry Laudan While it is a belief deeply ingrained in the legal community (and among the public) that false negatives are much more common than false positives (a 10:1 ratio being the preferred guess), […]
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Moving on from yesterday's discussion about Rational Numbers, what about irrational numbers, numbers which cannot be written as a ratio of two integers? Most whole numbers have square roots which are irrational numbers, but not everything with a radical is irrational. The square root of a perfect square is perfectly rational. So how can you tell if a number is a perfect square without a calculator? One way is through prime factorization. (Remember those factor trees from a long time ago.
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2:00 AM  Juillet 2015, 1er défi
Défi du calendrier mathématique 2015 : petit problème à résoudre….

Défis du Calendrier Mathématique
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Actualité
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nicholasgurewitch:
“Loring’s First Principle” (PBF#267): http://www.pbfcomics.com/267/
July 02, 2015
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11:27 PM  Artificial life which can be programmed
Artificial life which can be programmed __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________Filed under: Uncategorized Tagged: artificial intelligence, artificial life, chemlambda
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11:19 PM  Clutters I
I have been trying to firm up my feeling for the theory of clutters. To that end, I have been working through proofs of some elementary lemmas. For my future use, as much as anything else, I will post some … Continue reading →
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11:00 PM  On This Day in Math  July 3
Music is the pleasure the human mind experiences from counting without being aware that it is counting. ~Gottfried LeibnizThe 184th day of the year; 184 = 23 * 23 (concatenation of the first two primes).The smallest number that can be written as q * pq + r * p r, where p, q and r are distinct primes (184 = 3 * 23 + 5 * 25). *Prime CuriosJim Wilder @wilderlab pointed out that, with a properly placed zero in between, 1084 is the smallest integer whose spelling, one thousand
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10:55 PM  Gladly Paying $1.10 For a Dollar Bill...
....or why rational choices ain't always so rational:
Another lovely puzzle/paradox today from Greg Ross's "Futility Closet" volume. It's known as the "dollar auction" paradox created by economist Martin Schubik. The setup (I've adapted from Wikipedia):
An auctioneer is to auction off a single dollar bill with the following rule: the bill goes to the highest bidder, AND the
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10:47 PM  #mathsconf4
#mathsconf4 took place on Saturday 20th June in London and I was lucky enough to attend my second #mathsconf having been to the previous one in Birmingham. Check out my previous blog post on #mathsconf3 here.At #mathsconf4 I took part in 4 different sessions, each of which had their own things to share and I learnt a lot from each. I'll outline each of these below. However, before the first session we had the traditional 'speed dating' event. The event came with a lot more pressure this year  […]
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10:32 PM  La deuda griega
Buenas noches. Algo retrasado, os dejo mi entrada sobre la Deuda Griega. Espero que sea de vuestro agrado
http://matesdedavid.blogspot.com.es/2015/06/ladeudagriega.html
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10:29 PM  Tabulating Prediction Intervals in R
I just wrapped up (knock on wood!) a coding project using R and Shiny. (Shiny, while way cool, is incidental to this post.) It was a favor for a friend, something she intends to use teaching an online course. Two of the tasks, while fairly mundane, generated code that was just barely obscure enough to be possibly worth sharing. It's straight R code, so you need not use (or have installed) Shiny to use it.The first task was to output, in tabular form, the coefficients of a linear regression […]