Monthly Archives: January 2009

Mathematics, Science, and Blogs

Posted on January 28, 2009 by Gil Kalai

Michael Nielsen wrote a lovely essay entitled “Doing science online” about  mathematics, science,  and blogs. Michael’s primary example is a post over Terry Tao’s blog about the Navier-Stokes equation and he suggests blogs as a way of scaling up scientific conversation. Michael is writing … Continue reading →

Posted in Blogging, What is Mathematics | Tagged , , , , | 5 Comments

Test Your Intuition (3)

Posted on January 26, 2009 by Gil Kalai

Let be the -dimensional cube. Turn into a torus by identifying opposite facets. What is the minumum -dimensional volume of a subset of which intersects every non-trivial cycle in .

Posted in Geometry, Test your intuition | Tagged | 10 Comments

News

Posted on January 23, 2009 by Gil Kalai

  I just saw in “Shtetl Optimized” that the Linial-Nisan conjecture regarding circuits have been proved by Mark Braverman. Scott’s post describes the conjecture as well as related open problems in computational complexity. (Scott offers  $100 for a proof that Fourier … Continue reading →

Posted in Computer Science and Optimization | 3 Comments

Noise

Posted on January 23, 2009 by Gil Kalai

What is the correct picture of our world? Are noise and errors part of the essence of matters, and the beautiful perfect patterns we see around us, as well as the notions of information and computation, are just derived concepts … Continue reading →

Posted in Philosophy | 7 Comments

IPAM Fall 2009

Posted on January 20, 2009 by Gil Kalai

Combinatorics: Methods and Applications in Mathematics and Computer Science September 8 – December 11, 2009 Scientific overview: Combinatorics is a fundamental mathematical discipline as well as an essential component of many mathematical areas. It studies discrete objects and their properties. … Continue reading →

Posted in Conferences, Updates | Leave a comment

Solution

Posted on January 18, 2009 by Gil Kalai

The solution to the last riddle is:

Posted in Riddles | 4 Comments

Telling a Simple Polytope From its Graph

Posted on January 16, 2009 by Gil Kalai

Peter Mani  (a photograph by Emo Welzl) Simple polytopes, puzzles   Micha A. Perles conjectured in the ’70s that the graph of a simple -polytope determines the entire combinatorial structure of the polytope. This conjecture was proved in 1987 by Blind … Continue reading →

Posted in Convex polytopes, Open problems | Tagged , , | 8 Comments

A Riddle

Posted on January 15, 2009 by Gil Kalai

 What is this?    

Posted in Riddles | 13 Comments

The Retaliation Game

Posted on January 13, 2009 by Gil Kalai

  We have two players playing in turns. Each player can decide to stop in which case the game is stopped and the two players can go on with their lives, or to act. The player that acts gains and … Continue reading →

Posted in Games, Rationality | Tagged , , | 13 Comments

Links and Comments

Posted on January 12, 2009 by Gil Kalai

The link  L10n74  (click on the picture to see L10n74’s Braid representation, its Morse link presentation, its Alexander and Jones polynomials, its Khovanov homology, and more, much more.) Here are some links and further comments regarding the last four posts. (Mainly … Continue reading →

Posted in Controversies and debates | Tagged , , , , , , , , , | 4 Comments