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 What is mathematics (or at least, how it feels)
 Alef’s Corner
 To cheer you up in difficult times 22: some mathematical news! (Part 1)
 Cheerful News in Difficult Times: The Abel Prize is Awarded to László Lovász and Avi Wigderson
 Amazing: Feng Pan and Pan Zhang Announced a Way to “Spoof” (Classically Simulate) the Google’s Quantum Supremacy Circuit!
 To cheer you up in difficult times 21: Giles Gardam lecture and new result on Kaplansky’s conjectures
 Nostalgia corner: John Riordan’s referee report of my first paper
 At the Movies III: Picture a Scientist
 At the Movies II: Kobi Mizrahi’s short movie White Eye makes it to the Oscar’s short list.
Top Posts & Pages
 To cheer you up in difficult times 21: Giles Gardam lecture and new result on Kaplansky's conjectures
 Cheerful News in Difficult Times: The Abel Prize is Awarded to László Lovász and Avi Wigderson
 Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
 TYI 30: Expected number of Dice throws
 János Pach: Guth and Katz's Solution of Erdős's Distinct Distances Problem
 What is mathematics (or at least, how it feels)
 Extremal Combinatorics VI: The FranklWilson Theorem
 Amazing: Feng Pan and Pan Zhang Announced a Way to "Spoof" (Classically Simulate) the Google's Quantum Supremacy Circuit!
 Ringel Conjecture, Solved! Congratulations to Richard Montgomery, Alexey Pokrovskiy, and Benny Sudakov
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Category Archives: Combinatorics
The Argument Against Quantum Computers – A Very Short Introduction
Left: Gowers’s book Mathematics a very short introduction. Right C. elegans; Boson Sampling can be seen as the C. elegans of quantum computing. (See, this paper.) Update (January 6, 2021): Tomorrow January, 7, 8:30 AM Israel time, I give a … Continue reading
Posted in Combinatorics, Computer Science and Optimization, Physics, Probability, Quantum
Tagged Guy Kindler, quantum supremacy
7 Comments
Open problem session of HUJICOMBSEM: Problem #4, Eitan Bachmat: Weighted Statistics for Permutations
This is a continuation of our series of posts on the HUJI seminar 2020 open problems. This time the post was kindly written by Eitan Bachmat who proposed the problem. My summary: understanding of the distribution of largest increasing subsequences … Continue reading
To Cheer You Up in Difficult Times 15: Yuansi Chen Achieved a Major Breakthrough on Bourgain’s Slicing Problem and the Kannan, Lovász and Simonovits Conjecture
This post gives some background to a recent amazing breakthrough paper: An Almost Constant Lower Bound of the Isoperimetric Coefficient in the KLS Conjecture by Yuansi Chen. Congratulations Yuansi! The news Yuansi Chen gave an almost constant bounds for Bourgain’s … Continue reading
Posted in Combinatorics, Computer Science and Optimization, Convexity, Geometry
Tagged Yuansi Chen
5 Comments
Open problem session of HUJICOMBSEM: Problem #3, Ehud Friedgut – Independent sets and Lionel Levine’s infamous hat problem.
Here are the two problems presented by Ehud Friedgut. The first arose by Friedgut, Kindler, and me in the context of studying Lionel Levine’s infamous hat problem. The second is Lionel Levine’s infamous hat problem. Ehud Friedgut with a few … Continue reading
Posted in Combinatorics, Computer Science and Optimization, Probability
Tagged Ehud Friedgut, Guy Kindler, Lionel Levine
7 Comments
Open problem session of HUJICOMBSEM: Problem #2 Chaya Keller: The Krasnoselskii number
Marilyn Breen This is our second post on the open problem session of the HUJI combinatorics seminar. The video of the session is here. Today’s problem was presented by Chaya Keller. The Krasnoselskii number One of the bestknown applications … Continue reading
Posted in Combinatorics, Convexity
Tagged Chaya Keller, Marilyn Breen, Mark Krasnoselskii, Micha A. Perles
4 Comments
Photonic Huge Quantum Advantage ???
This is a quick and preliminary post about a very recent announcement in a Science Magazine paper: Quantum computational advantage using photons by a group of researchers leaded by Jianwei Pan and ChaoYang Lu. (Most of the researchers are from … Continue reading
Posted in Combinatorics, Physics, Probability, Quantum
Tagged BosonSampling, quantum supremacy
12 Comments
Recent progress on high dimensional TuranType problems by Andrey Kupavskii, Alexandr Polyanskii, István Tomon, and Dmitriy Zakharov and by Jason Long, Bhargav Narayanan, and Corrine Yap.
The extremal number for surfaces Andrey Kupavskii, Alexandr Polyanskii, István Tomon, Dmitriy Zakharov: The extremal number of surfaces Abstract: In 1973, Brown, Erdős and Sós proved that if is a 3uniform hypergraph on vertices which contains no triangulation of the sphere, then … Continue reading
Open problem session of HUJICOMBSEM: Problem #1, Nati Linial – Turan type theorems for simplicial complexes.
On November, 2020 we had a very nice open problem session in our weekly combinatorics seminar at HUJI. So I thought to have a series of posts to describe you the problems presented there. This is the first post in … Continue reading
Péter Pál Pach and Richárd Palincza: a Glimpse Beyond the Horizon
Prologue Consider the following problems: P3: What is the maximum density of a set A in without a 3term AP? (AP=arithmetic progression.) This is the celebrated Cap Set problem and we reported here in 2016 the breakthrough results by … Continue reading
Posted in Combinatorics, Geometry, Number theory, Open problems
Tagged Péter Pál Pach, Richárd Palincza
9 Comments
To cheer you up 14: Hong Liu and Richard Montgomery solved the Erdős and Hajnal’s odd cycle problem
The news: In 1981, Paul Erdős and András Hajnal asked whether the sum of the reciprocals of the odd cycle lengths in a graph with infinite chromatic number is necessarily infinite. Hong Liu and Richard Montgomery have just proved that … Continue reading
Posted in Combinatorics
Tagged András Hajnal, Carsten Thomassen, Hong Liu, Paul Erdos, Richard Montgomry
7 Comments