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389 posts tagged with Mathematics.

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## It's just a jump to the ... well, in any legal direction really

The Peg Solitaire Army is a problem spun off from a classic recreation, and yet another example of the golden ratio turning up where you least expect it. If you want to look at the game more deeply, George Bell's solitaire pages are the ne plus ultra: There's more about the solitaire army (and variants), ... [more inside]

## do while !glory

Welcome to Al Zimmermann's Programming Contests.

*You've entered an arena where demented computer programmers compete for glory and for some cool prizes.*The current challenge is just about to come to an end, but you can peruse the previous contests and prepare for the new one starting next month.## 2014 Fields Medals

The 2014 Fields Medals have been awarded to Artur Avila, Manjul Bhargava, Martin Hairer, and Maryam Mirzakhani. Mirzakhani, a professor at Stanford, is the first woman to win math's highest prize, and Avila is the first South American. Erica Klarreich at Quanta Magazine has profiles of all four winners. [more inside]

## Orchestrate Illusions (Superpermuter)

The Minimal Superpermutation Problem -

*Imagine that there is a TV series that you want to watch. The series consists of n episodes, with each episode on a single DVD. Unfortunately, however, the DVDs have become mixed up and the order of the episodes is in no way marked (and furthermore, the episodes of the TV show are not connected by any continuous storyline – there is no way to determine the order of the episodes just from watching them). Suppose that you want to watch the episodes of the TV series, consecutively, in the correct order. The question is: how many episodes must you watch in order to do this?*[more inside]## The Foehr Reef

The Foehr Reef is part of the worldwide Crochet Coral Reef Project. It was made by over 700 women and combines more than 4000 individual pieces of marine wonder. A short video shows its beauty [alternating English and German audio]. PDFs with pictures.
"The Crochet Coral Reef is a woolly celebration of the intersection of higher geometry and feminine handicraft, and a testimony to the disappearing wonders of the marine world." It originated out of a desire to increase awareness of environmental threats to the world's reefs and is a conjunction of art, environmentalism, and geometry. [more inside]

## 21st Century Wiener

Norbert Wiener: The Eccentric Genius Whose Time May Have Finally Come (Again) - "The most direct reason for Wiener's fall to relative obscurity was the breakthrough of a young mathematician and engineer named Claude Shannon." [more inside]

## musical mathematical journeys

Trio for Three Angles (1968) is one of many beautiful acclaimed visually-oriented short films with music by mathematical filmmakers Bruce and Katharine Cornwell, some animated by hand and some using early digital technology. It inspired three sequels: Similar Triangles (1975), Congruent Triangles (1976), and Journey to the Center of a Triangle (1978) (previously). [more inside]

## I'm leaving my body to science, not medical but physics

Let's Talk About Science is a blog devoted to discussing the world of science and technology communication with clear, beginner-friendly language, written and compiled by nanoscientist/physicist Jessamyn Fairfield and science educator ErinDubitably. [more inside]

## Following your heart is another tolerable option

## Math or Maths?

Math or Maths? A few minutes with Dr Lynne Murphy (an American linguist in England) should clear this right up. Via Numberphile.

## A SAT Attack on the Erdos Discrepancy Conjecture

Computers are providing solutions to math problems that we can't check - "A computer has solved the longstanding Erdős discrepancy problem! Trouble is, we have no idea what it's talking about — because the solution, which is as long as all of Wikipedia's pages combined, is far too voluminous for us puny humans to confirm." (via; previously ;)

## Visually stunning math concepts...

## Don't be gauche—guilloche!

Did you know there's a direct correlation between the decline in Spirograph popularity and the rise in gang activity? Reverse this deplorable trend by playing around with the Guilloché spiral pattern generator! [more inside]

## there is no soundtrack

Finite time blowup for an averaged three-dimensional Navier-Stokes equation - "[Terence Tao] has shown that in an alternative abstract universe closely related to the one described by the Navier-Stokes equations, it is possible for a body of fluid to form a sort of computer, which can build a self-replicating fluid robot that, like the Cat in the Hat, keeps transferring its energy to smaller and smaller copies of itself until the fluid 'blows up.' " [1,2,3] (previously)

## John Baez on the maths of connecting everyone (and everything) on earth

Network Theory Overview - "The idea: nature and the world of human technology are full of networks! People like to draw diagrams of networks. Mathematical physicists know that in principle these diagrams can be understood using category theory. But why should physicists have all the fun? This is the century of

*understanding living systems and adapting to life on a finite planet*. Math isn't the main thing we need, but it's got to be part of the solution... so one thing we should do is develop a unified and powerful theory of networks." (via ;)## "What is...." from the Notices of the American Math Society

Each month, the Notices of the American Math Society runs a column called "What is...." which aims to explain an advanced mathematical concept in two pages, at a level accessible to a good undergrad math major. Armin Straub, a postdoc at Illinois, has collected them all in one place. [more inside]

## The dangers of A/B testing

A/B testing has become a familiar term for most people running web sites, especially e-commerce sites. Unfortunately, most A/B test results are illusory (PDF, 312 kB). Here's how not to run an A/B test. Do use this sample size calculator or this weird trick.

## Truth & Beauty

The emotional experience of mathematical elegance. A new study by the perceptual neurobiologist Semir Zeki and the great mathematician (& Fields Medalist) Sir Michael Atiyah examines fMRI scans of mathematicians viewing formulae which they'd previously rated as beautiful or ugly, and reports that mathematical beauty elicits activity in the same brain regions as great art or music.

## And this one's the Half Double Decaf Half-Windsor, With A Twist of Lemon

## Network Nonsense

Open warfare erupts in the world of mathematical biology, as Lior Pachter of UC-Berkeley writes three blog posts attacking two papers in Nature Bioscience, accusing one of them of being "dishonest and fraudulent": The Network Nonsense of Albert-Laszlo Barabasi, The Network Nonsense of Manolo Kellis, and Why I Read the Network Nonsense Papers. Kellis (MIT) and his co-authors respond (.pdf.)

## How can nothing can be something?

While the concept of shunya or "zero", both as place holder in the decimal system and as "null" or "nothingness" has been historically attributed to the Indian mathematician/astronomer Aryabhata, it was when I went to search for its history and impact that whole new world was revealed. From culture and art to spiritual practice, the concept of zero has captured the imagination of many throughout the ages. Books have been written, its origins debated while the etymology of the word itself sometimes replaces understanding. From a disconcerting concept of nothingness to the ubiquitous misspelling of the one followed by a hundred zeros, Shunya today is more than just the gaping void it originally represented.

## One pill makes you nano, and one pill makes you giga...

The pressure of a human bite is about 1/9th of the atmospheric pressure on Venus. The fastest bacterium on earth is just outstripping the fastest glacier. A square meter of sunshine in the spring imparts about 1 horsepower. [more inside]

## Math with Bad Drawings

## binding the andat

Closing in on the twin prime conjecture (Quanta) - "Just months after Zhang announced his result, Maynard has presented an independent proof that pushes the gap down to 600. A new Polymath project is in the planning stages, to try to combine the collaboration's techniques with Maynard's approach to push this bound even lower." [more inside]

## ASCII fluid simulator

## Whoomp

*Slate's*Ben Blatt "sat in a Barnes & Noble for three hours flipping through all seven

*Where’s Waldo*books with a tape measure" and emerged with a method for finding Waldo with speed more than 50% of the time. [more inside]

## Card tricks...

...to leave a smile on your face, by Helder Guimarães: Individual vs Crowd | Chaos | Freedom | Trick [more inside]

## A number sentence for 5 cookies and 6 cups of whole milk?

The Washington Post reports on a ridiculous mathematics test for first graders administered under New York's Common Core standards initiative. [Common Core previously.]

## The sound of graph paper

GaMuSo is an application of BioGraph-based data mining to music, which helps you get recommendations for other musicians. Based on 140K user-defined tags from last.fm that are collected for over 400K artists, results are sorted by the "nearest" or most probable matches for your artist of interest (algorithm described here). [more inside]

## Evolved design

Unleashing Genetic Algorithms on the iOS 7 Icon - In the pursuit of something just a bit tighter than Marc Edwards' superellipse approximation, Mike Swanson applies genetic algorithms to the task of making a better button-making script.

## Papercraft project blog Paper Matrix

Paper Matrix is a blog that gives instructions for cool papercraft objects, "reinterpreting the Danish tradition of woven paper hearts and ornaments." Cut paper in the prescribed ways and weave it together carefully to make a mobile of colorful hot air balloons, gorgeous and complex boxes; simple but satisfying pennants and much more... including a full theater for performances by paper dolls.

## My God, it's full of... everything

Revelations in the field of quantum physics have resulted in the discovery of the Amplituhedron, a jewel-like higher dimensional object whose volume elegantly predicts fundamental physical processes that took the brilliant Dr. Richard Feynman hundreds of pages of abstruse mathematics to describe.
The theoretical manifold not only enables simple pen-and-paper calculation of physics that would normally require supercomputers to work out, but also challenges basic assumptions about the nature of reality -- forgoing the core concepts of locality and unitarity and suggesting that space and time are merely emergent properties of a timeless, infinitely-sided "master amplituhedron," whose geometry represents the sum total of all physical interactions.

**More:**The 152-page source paper on arXiv [PDF] - Lead author Nima Arkani-Hamed's hour-long lecture at SUSY 2013 - Scans of Arkani-Hamed's handwritten lecture notes - A far more detailed lecture series "Scattering Without Space Time": one, two, three - Arkani-Hamed previously on MeFi - A hot-off-the-presses Wikipedia page (watch this space)## A sine of the times

The Movie Math Quiz: Can you figure out which movies are being described by these mathematical equations?

## Dear Dylan

Wonkblog has a new advice column called "Dear Dylan" where Dylan Matthews answers the usual advice column staples using game theory, mathematics and charts.

## "Topics galore."

## music meets möbius

Making Music with a Möbius Strip : "It turns out that musical chords naturally inhabit various topological spaces, which show all the possible paths that a composer can use to move between chords. Surprisingly, the space of two-note chords is a Möbius strip."

## 15 ways to waste your day online with Tim Holman

tholman.com is the playground and folio of interactive developer Tim Holman, where he has posted 15 different projects, both interactive (fizzy cam [info/demo]; ZenPen; Texter; and Image Nodes) and passive (Meet the Ipsums, more than 30 text generators, from corporate to batman; the useless web; dripping paint). [more inside]

## Assume A Cylindrical Cow

## Ancient Greek Geometry: The Game

The regular polygons have been kidnapped by ninjas. Are you a bad enough dude/tte to construct the regular polygons with nothing but a virtual compass and straightedge? [more inside]

## If that sounds like it makes no sense that's because... well, it doesn't

This Simple Math Puzzle Will Melt Your Brain

"Adding and subtracting ones sounds simple, right? Not according to the old Italian mathematician Grandi—who showed that a simple addition of 1s and -1s can give three different answers."

"Adding and subtracting ones sounds simple, right? Not according to the old Italian mathematician Grandi—who showed that a simple addition of 1s and -1s can give three different answers."

## The Department Of War Math

You Are Not So Smart: Survivorship Bias, demonstrated through Abraham Wald's work at the Statistical Research Group in World War 2. [more inside]

## Proof and Community Standards

In August of last year, mathematician Shinichi Mochizuki reported that he had solved one of the great puzzles of number theory: the ABC conjecture (previously on Metafilter). Almost a year later, no one else knows whether he has succeeded. No one can understand his proof.

## Kenneth I. Appel (1932-2013)

Mathematician Kenneth Appel has died at the age of 80. He is best known for having proved, with Wolfgang Haken, the four-color theorem, which states that only four colors are needed to have a map in which no two adjacent countries have the same color. [more inside]

## Triple Gear

Mathematicians Henry Segerman and Saul Schleimer have produced a triple gear, three linked gears in space that can rotate together. A short writeup of the topology and geometry behind the triple gear on the arXiv.

## Computerized Math, Formal Proofs and Alternative Logic

Using computer systems for doing mathematical proofs - "With the proliferation of computer-assisted proofs that are all but impossible to check by hand, Hales thinks computers must become the judge." [more inside]

## Give or take

The origins of plus and minus signs - "There be other 2 signes in often use of which the first is made thus + and betokeneth more: the other is thus made – and betokeneth lesse."

## Aspiring Animators & Game Designers, Study Your Calculus & Combinatorics

Every film Pixar has produced has landed in the top fifty highest-grossing animated films of all time. What's their secret? Mathematics. Oh, and 22 Rules of Storytelling. [more inside]

## Will Redshirts by (Mefi's Own) John Scalzi have to be rewritten?

Bayesian analysis shows redshirts are not most likely to die on Star Trek:TOS.

*Although Enterprise crew members in redshirts suffer many more casualties than crew members in other uniforms, they suffer fewer casualties than crew members in gold uniforms when the entire population size is considered. Only 10% of the entire redshirt population was lost during the three year run of Star Trek. This is less than the 13.4% of goldshirts, but more than the 5.1% of blueshirts. What is truly hazardous is not wearing a redshirt, but being a member of the security department. The red-shirted members of security were only 20.9% of the entire crew, but there is a 61.9% chance that the next casualty is in a redshirt and 64.5% chance this red-shirted victim is a member of the security department. The remaining redshirts, operations and engineering make up the largest single population, but only have an 8.6% chance of being a casualty.*## OMG SCIENCE!

Henry Reich of Minute Physics shares his favorite science blogs, video channels, and other resources on the web. (Minute Physics previously) [more inside]