xEuclidx

Compass-and-straightedge construction (aka Euclidean construction) is a method of drawing precise geometric figures using only a compass and a straightedge (like a ruler without the markings). MathOpenRef maintains a catalog of many common constructions, each with an explanatory animation and a proof. This YouTube video demonstrates how to construct almost every polygon that can be constructed using these methods.
posted by jedicus on Sep 8, 2016 - 20 comments

The likelihood that there's interesting or important math is pretty high

Shinichi Mochizuki and the impenetrable proof - "Fesenko has studied Mochizuki's work in detail over the past year, visited him at RIMS again in the autumn of 2014 and says that he has now verified the proof. (The other three mathematicians who say they have corroborated it have also spent considerable time working alongside Mochizuki in Japan.) The overarching theme of inter-universal geometry, as Fesenko describes it, is that one must look at whole numbers in a different light — leaving addition aside and seeing the multiplication structure as something malleable and deformable. Standard multiplication would then be just one particular case of a family of structures, just as a circle is a special case of an ellipse." (previously: 1,2; via)
posted by kliuless on Oct 16, 2015 - 33 comments

HoTT Coq

Univalent Foundations Redefines Mathematics - "When a legendary mathematician found a mistake in his own work, he embarked on a computer-aided quest to eliminate human error. To succeed, he has to rewrite the century-old rules underlying all of mathematics." (previously)
posted by kliuless on Jun 9, 2015 - 13 comments

3Blue1Brown: Reminding the world that math makes sense

Understanding e to the pi i - "An intuitive explanation as to why e to the pi i equals -1 without a hint of calculus. This is not your usual Taylor series nonsense." (via via; reddit; previously)
posted by kliuless on Jun 6, 2015 - 28 comments

It's true because pictures

(1 + 2 + … + n)2 = (13 + 23 + … + n3) [animated GIF]
(unanimated version)
posted by Wolfdog on May 26, 2015 - 48 comments

there's nothing that is scientifically proven

(A theoretical physicist explains why) Science Is Not About Certainty
posted by flex on Aug 5, 2014 - 33 comments

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 ;)
posted by kliuless on Apr 12, 2014 - 24 comments

That’s why it doesn’t matter if God plays dice with the Universe

Discovering Free Will (Part II, Part III) - a nice discussion of the Conway-Kochen "Free Will Theorem".
posted by Wolfdog on Mar 4, 2014 - 92 comments

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.
posted by painquale on May 10, 2013 - 59 comments

"Maybe it's a sore point: your field should have an answer (people think you do) but there isn't one yet. Perhaps it's simple to pose but hard to answer. Or it's a question that belies a deep misunderstanding: the best answer is to question the question."
posted by the man of twists and turns on Apr 14, 2013 - 259 comments

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."
posted by kliuless on Mar 16, 2013 - 25 comments

Perhaps switch to strong English tea

The BBC reports that "Beer drinkers in the US have filed a \$5m (£3.3m) lawsuit accusing Anheuser-Busch of watering down its beer." The lawsuits are based on information from former employees at breweries owned by the multinational.
posted by Wordshore on Feb 27, 2013 - 125 comments

The strange case of The Pigeon-hole Principle

It's Saturday; why not think about the pigeonhole principle? Here are problems and more problems and what you might call a problem with the principle itself as it is often stated.
posted by Wolfdog on Nov 10, 2012 - 41 comments

From 100 to 0

The Royal Society of Chemistry is offering £1000 to the person or team producing the best and most creative explanation of the phenomenon, known today as The Mpemba Effect
posted by Kiwi on Jun 27, 2012 - 95 comments

Sure it's irrational! Just look!

Geometrically the irrationality of the square root of 2 means that there is no integer-by-integer square whose area is twice the area of another integer-by-integer square. A visual proof that the square root of 2 is irrational (not found in previous visual proof post.)
posted by Obscure Reference on May 9, 2012 - 39 comments

The Angel Problem

The Angel Problem. The Angel and the Devil play a game on an infinite chess board...
posted by Wolfdog on Feb 16, 2012 - 37 comments

Then you wouldn't have to say "QED", 'cause I'd already know

A thread full of proofs without words at MathOverflow and quite a lot more of them courtesy of Google Books.
posted by Wolfdog on Jul 18, 2011 - 22 comments

It Even Blocks the Endless Moaning

The First Zombie-Proof House: "The Safe House" was designed by KWK Promes, and completely folds in on itself to become an impenetrable concrete bunker, keeping you safe from the undead.
posted by bwg on May 6, 2011 - 82 comments

"Surely you can question my policies without questioning my faith. Or for that matter my citizenship." - President Obama

Handwritten 1961 memo in father's immigration file notes Obama born in Hawaii. "Documents obtained from the United States Citizenship and Immigration Service through a Freedom of Information Act request offer evidence that President Barack Obama was born in Hawaii. A memo dated Aug. 31, 1961 from William Wood of Immigration and Naturalization Services indicates that Barack Obama, Sr., was attending the University of Hawaii on a student visa and that a son, Barack Obama, II, was born in Honolulu on Aug, 8, 1961." [Image of Memo]
posted by Fizz on Apr 27, 2011 - 719 comments

Finite formula found for partition numbers

New math theories reveal the nature of numbers [1,2] - "We prove that partition numbers are 'fractal' for every prime. These numbers, in a way we make precise, are self-similar in a shocking way. Our 'zooming' procedure resolves several open conjectures, and it will change how mathematicians study partitions." (/.|via)
posted by kliuless on Jan 22, 2011 - 45 comments

Q to the E to the D

Futurama has always been a haven for geek humor, but last week's episode "The Prisoner of Benda" pushed things to the next level. First hinted at in an American Physical Society interview with showrunner David X. Cohen (previously), staff writer and mathematics Ph.D. Ken Keeler devised a novel mathematical proof based on group theory to resolve the logic puzzle spawned by the episode's brain-swapping (but no backsies!) conceit. Curious how it works? Read the proof (in the show or in plain text), then see it in action using this handy chart. Too much math for a lazy Sunday? Then entertain your brain with lengthy clips from the episode -- including two of the funniest moments in the series in the span of two minutes.
posted by Rhaomi on Aug 22, 2010 - 130 comments

Complex matters for the millenium

I am pleased to announce a proof that P is not equal to NP. In this paper, Vinay Deolalikar (HP Labs) proposes a proof to answer the most important problem in its field of mathematics.
posted by knz on Aug 8, 2010 - 113 comments

Position-based quantum cryptography theoretically proved

Our results open a fascinating new direction for position-based security in cryptography where security of protocols is solely based on the laws of physics and proofs of security do not require any pre-existing infrastructure.
posted by Joe Beese on Aug 8, 2010 - 47 comments

Did you know that you can create a simple set of directions to your house that works no matter where the recipient starts from? After 38 years this remarkable conjecture has now been proved by a 63-year old former security guard.
posted by unSane on Mar 21, 2008 - 46 comments

Photography(proof) for the blind(skeptics)

How do you prove photography to a blind man?
posted by carmina on Mar 26, 2007 - 21 comments

The Duke lacrosse rape case

The Duke lacrosse rape case hurtled toward perhaps sinister motives last week with testimony from the head of the private DNA lab prosecutor Nifong hired to test the rape kit samples taken from the accuser. Brian Meehan revealed that not only had his lab found DNA samples from five unknown men, none of whom were Duke lacrosse players, Meehan had also agreed with Nifong not to put that info in the DNA Security's final report. Were it not for the fact that the three defendants have counsel capable of pouring over thousands of pages of technical documents, this vital, exculpatory evidence would have gone unnoticed. Previous opinions in MeFi.
posted by semmi on Dec 22, 2006 - 276 comments

Proofs and Pictures: The Role of Visualization in Mathematical and Scientific Reasoning

Proofs and Pictures: The Role of Visualization in Mathematical and Scientific Reasoning [video] "The picture is a telescope for looking into Plato's heaven." -- James Brown [cached]
posted by Chuckles on Aug 20, 2006 - 27 comments

Success Often Endangers Rappers

Mercury News D-12's Proof, shot dead at 32. Proof stayed close to give back what he owed - and paid with his life.
posted by archkim on Apr 12, 2006 - 96 comments

There is a website that successfully argues for the existence of God.Here is the URL.Therefore, God exists.

Over 300 Proofs of God's Existence!
posted by Citizen Premier on Aug 25, 2005 - 170 comments

Nerdy proof that girls are evil.

Nerdy proof that girls are evil.
posted by betobeto on May 18, 2001 - 13 comments

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