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Recent Posts
- Richard Stanley: Enumerative and Algebraic Combinatorics in the1960’s and 1970’s
- Igor Pak: How I chose Enumerative Combinatorics
- Quantum Computers: A Brief Assessment of Progress in the Past Decade
- Noga Alon and Udi Hrushovski won the 2022 Shaw Prize
- Oliver Janzer and Benny Sudakov Settled the Erdős-Sauer Problem
- Past and Future Events
- Joshua Hinman proved Bárány’s conjecture on face numbers of polytopes, and Lei Xue proved a lower bound conjecture by Grünbaum.
- Amazing: Jinyoung Park and Huy Tuan Pham settled the expectation threshold conjecture!
- Combinatorial Convexity: A Wonderful New Book by Imre Bárány
Top Posts & Pages
- Quantum Computers: A Brief Assessment of Progress in the Past Decade
- Igor Pak: How I chose Enumerative Combinatorics
- Oliver Janzer and Benny Sudakov Settled the Erdős-Sauer Problem
- Richard Stanley: Enumerative and Algebraic Combinatorics in the1960’s and 1970’s
- Richard Stanley: How the Proof of the Upper Bound Theorem (for spheres) was Found
- The Argument Against Quantum Computers - A Very Short Introduction
- A sensation in the morning news - Yaroslav Shitov: Counterexamples to Hedetniemi's conjecture.
- Amazing: Jinyoung Park and Huy Tuan Pham settled the expectation threshold conjecture!
- To cheer you up in difficult times 13: Triangulating real projective spaces with subexponentially many vertices
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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 Frankl-Wilson 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