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Recent Posts
 Hoi Nguyen and Melanie Wood: Remarkable Formulas for the Probability that Projections of Lattices are Surjective
 Petra! Jordan!
 The largest clique in the Paley Graph: unexpected significant progress and surprising connections.
 Thinking about the people of Wuhan and China
 Ringel Conjecture, Solved! Congratulations to Richard Montgomery, Alexey Pokrovskiy, and Benny Sudakov
 Test your intuition 43: Distribution According to Areas in Top Departments.
 Two talks at HUJI: on the “infamous lower tail” and TOMORROW on recent advances in combinatorics
 Amazing: Zhengfeng Ji, Anand Natarajan, Thomas Vidick, John Wright, and Henry Yuen proved that MIP* = RE and thus disproved Connes 1976 Embedding Conjecture, and provided a negative answer to Tsirelson’s problem.
 Do Not Miss: Abel in Jerusalem, Sunday, January 12, 2020
Top Posts & Pages
 Hoi Nguyen and Melanie Wood: Remarkable Formulas for the Probability that Projections of Lattices are Surjective
 Aubrey de Grey: The chromatic number of the plane is at least 5
 Konstantin Tikhomirov: The Probability that a Bernoulli Matrix is Singular
 Elchanan Mossel's Amazing Dice Paradox (your answers to TYI 30)
 Ringel Conjecture, Solved! Congratulations to Richard Montgomery, Alexey Pokrovskiy, and Benny Sudakov
 Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
 Gil's Collegial Quantum Supremacy Skepticism FAQ
 Coloring Problems for Arrangements of Circles (and Pseudocircles)
 Amazing! Keith Frankston, Jeff Kahn, Bhargav Narayanan, Jinyoung Park: Thresholds versus fractional expectationthresholds
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Monthly Archives: June 2009
Test Your Intuition (6)
This is not as clear cut a question as the earlier ones, and if you do not know an answer then it will be difficult to figure one out just based on intuition. (But perhaps possible). If you are intrigued by … Continue reading
Praise For ‘Gina says’
Praise for: ” ‘Gina Says,’ Adventures in the Blogsphere String War (Below the dividing line: Greg Kuperberg, Scott Aaronson, Clifford Johnson, Peter Woit, Motty Perry, Caterina Calsamiglia, Yuval Peres, Eva Illouz, and (right from the comment section) Luca Trevisan, Thomas … Continue reading
Posted in Book review, Gina Says
11 Comments
My Book: “Gina Says,” Adventures in the Blogosphere String War
Update (November 2017): I received an advanced copy. How exciting! Update (October 2017): The much changed version of the book with beautiful drawing by my daughter Neta Kalai is soon to appear in print. It is published by World Scientific. Here … Continue reading
Posted in Blogging, Gina Says
36 Comments
Borsuk’s Conjecture
Karol Borsuk conjectured in 1933 that every bounded set in can be covered by sets of smaller diameter. Jeff Kahn and I found a counterexample in 1993. It is based on the FranklWilson theorem. Let be the set of vectors of length . … Continue reading
Banknotes with Pictures of Mathematicians
Are you aware of any? (current ones? old ones?)
Posted in Uncategorized
12 Comments
Test Your Intuition (5)
(Not such a set) consider a planar set A with the following property. In every direction, the distance between the two parallel lines that touch A from both sides is the same! Must A be a circle?
Answer To Test Your Intuition (4)
Let G be a graph and u and v two vertices. (1) Let H be a random graph where every edge of G is chosen with probability ½. Let p be the probability that there is a path between u … Continue reading
Test Your Intuition (4)
Let G be a graph and u and v two vertices. (1) Let H be a random graph where every edge of G is chosen with probability ½. Let p be the probability that there is a path between u … Continue reading
Posted in Probability
18 Comments