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 First third of my ICM2018 paper – Three Puzzles on Mathematics, Computation and Games. Corrections and comments welcome
 Preview: The solution by Keller and Lifshitz to several open problems in extremal combinatorics
 Basic Notions Seminar is Back! Helly Type Theorems and the Cascade Conjecture
 My Very First Book “Gina Says”, Now Published by “World Scientific”
 Itai Benjamini: Coarse Uniformization and Percolation & A Paper by Itai and me in Honor of Lucio Russo
 AfterDinner Speech for Alex Lubotzky
 Boaz Barak: The different forms of quantum computing skepticism
 Bálint Virág: Random matrices for Russ
 Test Your Intuition 33: The Great Free Will Poll
Top Posts & Pages
 First third of my ICM2018 paper  Three Puzzles on Mathematics, Computation and Games. Corrections and comments welcome
 Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
 Preview: The solution by Keller and Lifshitz to several open problems in extremal combinatorics
 Elchanan Mossel's Amazing Dice Paradox (your answers to TYI 30)
 TYI 30: Expected number of Dice throws
 Can Category Theory Serve as the Foundation of Mathematics?
 If Quantum Computers are not Possible Why are Classical Computers Possible?
 Eran Nevo: gconjecture part 4, Generalizations and Special Cases
 Polymath 10 Emergency Post 5: The ErdosSzemeredi Sunflower Conjecture is Now Proven.
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Monthly Archives: July 2008
A Diamater Problem for Families of Sets.
Let me draw your attention to the following problem: Consider a family of subsets of size d of the set N={1,2,…,n}. Associate to a graph as follows: The vertices of are simply the sets in . Two vertices and are adjacent … Continue reading
Posted in Combinatorics, Convex polytopes, Open problems
10 Comments
Extremal Combinatorics II: Some Geometry and Number Theory
Extremal problems in additive number theory Our first lecture dealt with extremal problems for families of sets. In this lecture we will consider extremal problems for sets of real numbers, and for geometric configurations in planar Euclidean geometry. Problem I: Given a set A of … Continue reading
Arrow’s Economics 1
The annual Summer School in Economics at HU was directed until last year by Kenneth Arrow, along with Eyal Winter. Arrow decided this year to step down as a director and Eric Maskin is replacing him. The 2008 Summer School was … Continue reading
Pushing Behrend Around
Erdos and Turan asked in 1936: What is the largest subset of {1,2,…,n} without a 3term arithmetic progression? In 1946 Behrend found an example with Now, sixty years later, Michael Elkin pushed the the factor from the denominator to the enumerator, … Continue reading
Posted in Combinatorics, Updates
Tagged Arithmetic progressions, Roth's theorem, Szemeredi's theorem
10 Comments
From Helly to Cayley IV: Probability
I decided to split long part III into two parts. This (truly) last part of this series deals with probabilistic problems and with combinatorial questions regarding higher Laplacians. 21. Higher Laplacians and their meanings Our high dimensional extension to Cayley’s … Continue reading
Posted in Combinatorics, Probability
8 Comments
A New RectorElect at the Hebrew University of Jerusalem
Professor Sarah Stroumsa On Wednesday, the Senate of the Hebrew University of Jerusalem elected Professor Sarah Stroumsa (homepage) as the next Rector (provost) of the Hebrew University. For the first time since its establishment, the Hebrew University has elected a woman to its highest post … Continue reading
Helly, Cayley, Hypertrees, and Weighted Enumeration III
This is the third and last part of the journey from a Helly type conjecture of Katchalski and Perles to a Cayley’s type formula for “hypertrees”. (On second thought I decided to divide it into two devoting the second to probabilistic questions.) … Continue reading
Posted in Combinatorics, Convexity, Open problems, Probability
7 Comments