The Nature of Computation
- Intellects Vast and Warm and Sympathetic
: "I hand you a network or graph, and ask whether there is a path through the network that crosses each edge exactly once, returning to its starting point. (That is, I ask whether there is a 'Eulerian' cycle.) Then I hand you another network, and ask whether there is a path which visits each node exactly once. (That is, I ask whether there is a 'Hamiltonian' cycle.) How hard is it to answer me?" (via
) [more inside]
posted by kliuless
on Dec 1, 2012 -
Morton and Vicary on the Categorified Heisenberg Algebra
- "In quantum mechanics, position times momentum does not equal momentum times position! This sounds weird, but it's connected to a very simple fact. Suppose you have a box with some balls in it, and you have the magical ability to create and annihilate balls. Then there's one more way to create a ball and then annihilate one, than to annihilate one and then create one. Huh? Yes: if there are, say, 3 balls in the box to start with, there are 4 balls you can choose to annihilate after you've created one but only 3 before you create one..." [more inside]
posted by kliuless
on Jul 21, 2012 -
The trend of mathematics and physics towards unification provides the physicist with a powerful new method of research into the foundations of his subject, a method which has not yet been applied successfully, but which I feel confident will prove its value in the future. The method is to begin by choosing that branch of mathematics which one thinks will form the basis of the new theory. One should be influenced very much in this choice by considerations of mathematical beauty.
 [more inside]
posted by smcg
on Apr 28, 2012 -
Before it was a website, Ask A Mathematician / Ask A Physicist was two guys sitting in the desert at Burning Man, presuming to answer (almost) any question that happened to occur to whomever happened to appear at our stand. [more inside]
posted by Obscure Reference
on Aug 27, 2011 -
The 300th issue
of This Week's Finds in Mathematical Physics
will be the last. It is not an exaggeration to say that when John Baez
started publishing TWF in 1993, he invented the science blog, and an (academic) generation has now grown up reading his thoughts on higher category theory
, zeta functions
, quantum gravity
, crazy pictures of roots of polynomials
, science fiction
, and everything else that can loosely be called either "mathematical" or "physics."
Baez continues to blog actively at n-category cafe
and the associated nLab
(an intriguingly fermented commune of mathematicians, physicists, and philosophers.) He is now starting a new blog, Azimuth
, "centered around the theme of what scientists can do to help save the planet
posted by escabeche
on Aug 14, 2010 -
"I can see the audience tonight, so I can see also from the size of it that there must many of you here who are not thoroughly familiar with physics, and also a number that are not too versed in mathematics- and I don't doubt that there are some who know neither physics nor mathematics very well.
That puts a considerable challenge on a speaker who is going to speak on the relation of physics and mathematics- a challenge which I, however, will not accept: I published the title of the talk in clear and precise language, and didn't make it sound like it was something it wasn't- it's the relation of physics and mathematics - and if you find that in some spots it assumes some minor knowledge of physics or mathematics, I cannot help it. It was named."
The Feynman Messenger series at Cornell
has been made available online for the first time thanks to Bill Gates.
posted by hindmost
on Jul 15, 2009 -
The Logic of Diversity
"A new book, The Wisdom of Crowds
] by The New Yorker
columnist James Surowiecki, has recently popularized the idea that groups can, in some ways, be smarter than their members, which is superficially similar to Page's results
. While Surowiecki gives many examples of what one might call collective cognition, where groups out-perform isolated individuals, he really has only one explanation for this phenomenon, based on one of his examples: jelly beans [...
] averaging together many independent, unbiased guesses gives a result that is probably closer to the truth than any one guess. While true — it's the central limit theorem
of statistics — it's far from being the only way in which diversity
can be beneficial in problem solving." (Three-Toed Sloth)
posted by kliuless
on Jun 20, 2005 -
'The Poincare Conjecture' Solved?
"Dr Grigori Perelman, of the Steklov Institute of Mathematics of the Russian Academy of Sciences, St Petersburg, claims to have proved the Poincare Conjecture, one of the most famous problems in mathematics. The Poincare Conjecture, an idea about three-dimensional objects, has haunted mathematicians for nearly a century. If it has been solved, the consequences will reverberate throughout geometry and physics."
Also of note is that Perelman's solution is only a benign side effect of his efforts toward defining all three-dimensional surfaces mathematically, which if successful would allow humanity to "produce a catalogue of all possible three-dimensional shapes in the Universe, meaning that [mankind] could ultimately describe the actual shape of the cosmos itself."
posted by eyebeam
on May 8, 2003 -
has finished his book, "A New Kind of Science
," which purpotedly is being espoused as a paradigm shift in many fields. But, I'm starting to see a very reductionistic attitude in many of the main theorists of complextity theory and emergent phenomena. Is the idea that the Universe is in lines of code a phallus-extension/masculine overdriven idea? Isn't math a man made mapping and can the Universe be reduced to an equation by a man? Still this book is going to be groundbreaking. Read the following exceperpt from the wired.com
q: "I've got to ask you," I say. "How long do you envision this rule of the universe to be?"
w: "I'm guessing it's really very short."
q: "Like how long?"
w: "I don't know. In Mathematica, for example, perhaps three, four lines of code."
link via protofunk.org
, old similar thread
posted by nakedjon
on May 20, 2002 -
Another unified theory!
And this time it's not just about physics, but the eternity domain, diallel lines, sunspots, egg resonance, planetary alignment, plant dehydration and the Book of Mormon too.
posted by rodii
on Feb 4, 2001 -