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Recent Posts
- My Notices AMS Paper on Quantum Computers – Eight Years Later, a Lecture by Dorit Aharonov, and a Toast to Michael Ben-Or
- Arturo Merino, Torsten Mütze, and Namrata Apply Gliders for Hamiltonicty!
- Updates from Cambridge
- Random Circuit Sampling: Fourier Expansion and Statistics
- Plans and Updates: Complementary Pictures
- Updates and Plans IV
- Three Remarkable Quantum Events at the Simons Institute for the Theory of Computing in Berkeley
- Yair Shenfeld and Ramon van Handel Settled (for polytopes) the Equality Cases For The Alexandrov-Fenchel Inequalities
- On the Limit of the Linear Programming Bound for Codes and Packing
Top Posts & Pages
- My Notices AMS Paper on Quantum Computers - Eight Years Later, a Lecture by Dorit Aharonov, and a Toast to Michael Ben-Or
- Navier-Stokes Fluid Computers
- Arturo Merino, Torsten Mütze, and Namrata Apply Gliders for Hamiltonicty!
- Updates and plans III.
- TYI 30: Expected number of Dice throws
- Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
- Elchanan Mossel's Amazing Dice Paradox (your answers to TYI 30)
- Marcelo Campos, Matthew Jenssen, Marcus Michelen and, and Julian Sahasrabudhe: Striking new Lower Bounds for Sphere Packing in High Dimensions
- An interview with Noga Alon
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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 3-term 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
15 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 Rector-Elect 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