Recent Comments

Recent Posts
 Mathematical Gymnastics
 Media Item from “Haaretz” Today: “For the first time ever…”
 Jim Geelen, Bert Gerards, and Geoﬀ Whittle Solved Rota’s Conjecture on Matroids
 Media items on David, Amnon, and Nathan
 Next Week in Jerusalem: Special Day on Quantum PCP, Quantum Codes, Simplicial Complexes and Locally Testable Codes
 Happy Birthday Ervin, János, Péter, and Zoli!
 My Mathematical Dialogue with Jürgen Eckhoff
 Test Your Intuition (23): How Many Women?
 Happy Birthday Richard Stanley!
Top Posts & Pages
 The KadisonSinger Conjecture has beed Proved by Adam Marcus, Dan Spielman, and Nikhil Srivastava
 Believing that the Earth is Round When it Matters
 János Pach: Guth and Katz's Solution of Erdős's Distinct Distances Problem
 Polymath 8  a Success!
 Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
 Analysis of Boolean Functions
 The Ultimate Riddle
 Two Math Riddles
 When It Rains It Pours
RSS
Author Archives: Gil Kalai
The KadisonSinger Conjecture has beed Proved by Adam Marcus, Dan Spielman, and Nikhil Srivastava
…while we keep discussing why mathematics is possible… The news Adam Marcus, Dan Spielman, and Nikhil Srivastava posted a paper entitled “Interlacing Families II: Mixed Characteristic Polynomials and the KadisonSinger Problem,” where they prove the 1959 KadisonSinger conjecture. (We discussed part … Continue reading
Why is Mathematics Possible: Tim Gowers’s Take on the Matter
In a previous post I mentioned the question of why is mathematics possible. Among the interesting comments to the post, here is a comment by Tim Gowers: “Maybe the following would be a way of rephrasing your question. We know … Continue reading
Posted in Open discussion, Philosophy, What is Mathematics
Tagged Foundations of Mathematics, Open discussion, Philosophy, Tim Gowers
23 Comments
Polymath8: Bounded Gaps Between Primes
Yitang Zhang’s very recent shocking paper demonstrated that bounded gaps between primes occur infinitely often, with the explicit upper bound of 70,000,000 given for this gap. Polymath8 was launched for the dual purpose of learning Zhang’s proof and improving the upper bound … Continue reading
Posted in Mathematics over the Internet, Number theory, Updates
Tagged Polymath8, Twin primes conjecture
Leave a comment
Joram’s Memorial Conference
Joram Lindenstrauss 19362012 This week our local Institute of Advanced Study holds a memorial conference for Joram Lindenstrauss. Joram was an immensely powerful mathematician, in terms of originality and conceptual vision, in terms of technical power, in terms of courage to confront … Continue reading
Andriy Bondarenko Showed that Borsuk’s Conjecture is False for Dimensions Greater Than 65!
The news in brief Andriy V. Bondarenko proved in his remarkable paper The Borsuk Conjecture for twodistance sets that the Borsuk’s conjecture is false for all dimensions greater than 65. This is a substantial improvement of the earlier record (all dimensions … Continue reading
Why is mathematics possible?
Spectacular advances in number theory Last weeks we heard about two spectacular results in number theory. As announced in Nature, Yitang Zhang proved that there are infinitely many pairs of consecutive primes which are at most 70 million apart! This is a sensational achievement. … Continue reading
Dan Mostow on Haaretz and Other Updates
Enlightenment at a red traffic light Wolf Prize laureate Prof. George Daniel Mostow made his greatest scientific breakthrough while driving. Haaretz tells the story of how Dan Mostow reached his breakthrough known as Mostow’s rigidity theorem. Congratulations, Dan! FrenchIsreali Meeting … Continue reading
Test Your Intuition (21): Auctions
You run a singleitem sealed bid auction where you sell an old camera. There are three bidders and the value of the camera for each of them is described by a certain (known) random variable: With probability 0.9 the value … Continue reading
Posted in Economics, Games, Test your intuition
Tagged Auctions, Roger Myerson, Test your intuition
4 Comments
Oz’ Balls Problem: The Solution
A commentator named Oz proposed the following question: You have a box with n red balls and n blue balls. You take out each time a ball at random but, if the ball was red, you put it back in the box and take out … Continue reading
Posted in Probability, Test your intuition
Tagged Erosion, J. F. C. Kingman, Probability, S. E. Volkov
1 Comment
Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
Yeshu Kolodni and Lord Kelvin The question In 1862, the physicist William Thomson (who later became Lord Kelvin) of Glasgow published calculations that fixed the age of Earth at between 20 million and 400 … Continue reading
Posted in Geology, Physics, Test your intuition
4 Comments