Category Archives: Geometry

Open problem session of HUJI-COMBSEM: 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

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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 3-term AP? (AP=arithmetic progression.) This is the celebrated Cap Set problem and we reported here in 2016 the breakthrough results by … Continue reading

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To cheer you up in difficult times 13: Triangulating real projective spaces with subexponentially many vertices

Wolfgang Kühnel Today I want to talk about a new result in a newly arXived paper: A subexponential size by Karim Adiprasito, Sergey Avvakumov, and Roman Karasev. Sergey Avvakumov gave about it a great zoom seminar talk about the result … Continue reading

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Alef’s Corner: Math Collaboration 2

Other Alef’s corner posts

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Or Ordentlich, Oded Regev and Barak Weiss: New bounds for Covering Density!

Update (June 3, 2020): The paper New bounds on the density of lattice coverings is now on the arXiv. Barak Weiss lectured about his breakthrough results with Or Ordentlich, and Oded Regev, at a Simons Institute workshop: Lattices: Geometry, Algorithms and … Continue reading

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To cheer you up in complicated times – A book proof by Rom Pinchasi and Alexandr Polyanskii for a 1978 Conjecture by Erdős and Purdy!

Things do not look that good, and these are difficult times. But here on the blog we have plenty of things to cheer you up and assure you. And today we point to two book proofs — two book proofs … Continue reading

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Do Not Miss: Abel in Jerusalem, Sunday, January 12, 2020

From left: Christopher Hacon, Claire Voisin, Ulrike Tillmann,  François Labourie Update: This was a great event with four great inspiring talks. Abel in Jerusalem, January 12, 2020 The Einstein Institute of mathematics is happy to host the Abel in Jerusalem Conference “Abel in … Continue reading

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Gil Bor, Luis Hernández-Lamoneda, Valentín Jiménez-Desantiago, and Luis Montejano-Peimbert: On the isometric conjecture of Banach

Stefan Banach and one of his famous quotes. Is it really true? A commentator (troll?) named Gina tried to challenge it in a heated discussion over the n-Category cafe. This post briefly describes a May 2019 paper On the isometric conjecture … Continue reading

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Abel in Jerusalem – SUNDAY, January 12, 2020, and other events

Update: Boris Solomyak’s birthday conference (January 13-14, Bar-Ilan University)is now added. I would like to report on seven eight nine ten mathematical events taking place in Jerusalem, the Tel Aviv area, and Haifa in the next few weeks. (Probably I … Continue reading

Posted in Algebra, Analysis, Combinatorics, Computer Science and Optimization, Conferences, Geometry, Updates | Tagged , , , | 1 Comment

Old lecture notes by Alex Zabrodsky

The next post will announce several mathematical events taking place in the next few weeks in Israel. One of these events is the Zabrodsky lectures at the Hebrew University of Jerusalem, that are given this year by Paul Seidel, starting … Continue reading

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