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 Game Theory – online Course at IDC, Herzliya
 TYI44: “What Then, To Raise an Old Question, is Mathematics?”
 Kelman, Kindler, Lifshitz, Minzer, and Safra: Towards the EntropyInfluence Conjecture
 Or Ordentlich, Oded Regev and Barak Weiss: New bounds for Covering Density!
 To cheer you up in complicated times – A book proof by Rom Pinchasi and Alexandr Polyanskii for a 1978 Conjecture by Erdős and Purdy!
 A new PolyTCS blog!
 Remarkable New Stochastic Methods in ABF: Ronen Eldan and Renan Gross Found a New Proof for KKL and Settled a Conjecture by Talagrand
 Hoi Nguyen and Melanie Wood: Remarkable Formulas for the Probability that Projections of Lattices are Surjective
 Petra! Jordan!
Top Posts & Pages
 Game Theory  online Course at IDC, Herzliya
 TYI44: "What Then, To Raise an Old Question, is Mathematics?"
 Kelman, Kindler, Lifshitz, Minzer, and Safra: Towards the EntropyInfluence Conjecture
 TYI 30: Expected number of Dice throws
 To cheer you up in complicated times  A book proof by Rom Pinchasi and Alexandr Polyanskii for a 1978 Conjecture by Erdős and Purdy!
 When Do a Few Colors Suffice?
 A sensation in the morning news  Yaroslav Shitov: Counterexamples to Hedetniemi's conjecture.
 The seventeen camels riddle, and Noga Alon's camel proof and algorithms
 Quantum computers: amazing progress (Google & IBM), and extraordinary but probably false supremacy claims (Google).
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Category Archives: Convexity
Isabella Novik and Hailun Zheng: Neighborly centrally symmetric spheres exist in all dimensions!
A tweetlong summary: The cyclic polytope is wonderful and whenever we construct an analogous object we are happy. Examples: Neighborly cubic polytopes; The amplituhedron; and as of last week, the NovikZheng new construction of neighborly centrally symmetric spheres! At last: … Continue reading
News on Fractional Helly, Colorful Helly, and Radon
My 1983 Ph D thesis was on Hellytype theorems which is an exciting part of discrete geometry and, in the last two decades, I have had an ongoing research project with Roy Meshulam on topological Hellytype theorems. The subject found … Continue reading
Attila Por’s Universality Result for Tverberg Partitions
In this post I would like to tell you about three papers and three theorems. I am thankful to Moshe White and Imre Barany for helpful discussions. a) Universality of vector sequences and universality of Tverberg partitions, by Attila Por; Theorem … Continue reading
Jean
Jean Bourgain and Joram Lindenstrauss. I was very sad to hear that Jean Bourgain, among the greatest mathematicians of our time, and a dear friend, passed away. I first met Jean about forty years ago and later we became friends … Continue reading
Posted in Analysis, Combinatorics, Computer Science and Optimization, Convexity, Number theory, Obituary
Tagged Jean Bourgain
5 Comments
Ricky and Branko
Two dear friends, and great geometers, Ricky Pollack and Branko Grünbaum passed away a few weeks ago. Ricky was a close friend that both Mazi my wife and I loved, and we were both fascinated by his wisdom, charm and … Continue reading
Posted in Combinatorics, Convexity, Geometry, Obituary
Tagged Branko Grunbaum, Ricky Pollack
3 Comments
Nathan Rubin Improved the Bound for Planar Weak εNets and Other News From EinGedi
I just came back from a splendid visit to Singapore and Vietnam and I will write about it later. While I was away, Nathan Rubin organized a lovely conference on topics closed to my heart ERC Workshop: Geometric Transversals and EpsilonNets with … Continue reading
Basic Notions Seminar is Back! Helly Type Theorems and the Cascade Conjecture
Kazhdan’s Basic Notion Seminar is back! The “basic notion seminar” is an initiative of David Kazhdan who joined the Hebrew University math department around 2000. People give series of lectures about basic mathematics (or not so basic at times). Usually, speakers do … Continue reading
Posted in Combinatorics, Convexity, Open problems
Tagged David Kazhdan, Helly type theorems, Tverberg's theorem
4 Comments
From Oberwolfach: The Topological Tverberg Conjecture is False
The topological Tverberg conjecture (discussed in this post), a holy grail of topological combinatorics, was refuted! The threepage paper “Counterexamples to the topological Tverberg conjecture” by Florian Frick gives a brilliant proof that the conjecture is false. The proof is … Continue reading
Posted in Combinatorics, Conferences, Convexity, Updates
Tagged Florian Frick, Issac Mabillard, Oberwolfach, Uli Wagner
3 Comments
Around Borsuk’s Conjecture 3: How to Save Borsuk’s conjecture
Borsuk asked in 1933 if every bounded set K of diameter 1 in can be covered by d+1 sets of smaller diameter. A positive answer was referred to as the “Borsuk Conjecture,” and it was disproved by Jeff Kahn and me in 1993. … Continue reading