Category Archives: Combinatorics

Richard Stanley: Enumerative and Algebraic Combinatorics in the1960’s and 1970’s

In his comment to the previous post by Igor Pak, Joe Malkevitch referred us to a wonderful paper by Richard Stanley on enumerative and algebraic combinatorics in the 1960’s and 1970’s. See also this post on Richard’s memories regarding the … Continue reading

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Igor Pak: How I chose Enumerative Combinatorics

Originally posted on Igor Pak's blog:
Apologies for not writing anything for awhile. After Feb 24, the math part of the “life and math” slogan lost a bit of relevance, while the actual events were stupefying to the point…

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Oliver Janzer and Benny Sudakov Settled the Erdős-Sauer Problem

Norbert Sauer The news in brief:  In the new paper Resolution of the Erdős-Sauer problem on regular subgraphs Oliver Janzer and Benny Sudakov proved that any graph G with vertices and more than edges contains a k-regular subgraph. This bound … Continue reading

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Past and Future Events

Quick announcements of past (recorded) and future events 1) Shachar Lovett was the Erdos Speaker for 2022 and his great talks are recorded. (Lecture 1, Tensor ranks and their applications lecture 2, The monomial structure of Boolean functions, lecture 3, … Continue reading

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Joshua Hinman proved Bárány’s conjecture on face numbers of polytopes, and Lei Xue proved a lower bound conjecture by Grünbaum.

Joshua Hinman proved Bárány’s conjecture. One of my first posts on this blog was a 2008 post Five Open Problems Regarding Convex Polytopes, now 14 years later, I can tell you about the first problem on the list to get solved. … Continue reading

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Amazing: Jinyoung Park and Huy Tuan Pham settled the expectation threshold conjecture!

A brief summary: In the paper, A proof of the Kahn-Kalai conjecture, Jinyoung Park and Huy Tuan Pham proved the 2006 expectation threshold conjecture posed by Jeff Kahn and me. The proof is wonderful. Congratulations Jinyoung and Huy Tuan! Updates: … Continue reading

Posted in Combinatorics, Probability | Tagged , | 5 Comments

Combinatorial Convexity: A Wonderful New Book by Imre Bárány

A few days ago I received by mail Imre Bárány’s new book Combinatorial Convexity. The book presents Helly-type theorems and other results in convexity with combinatorial flavour. The choice of material and the choice of proofs is terrific and it … Continue reading

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Chaim Even-Zohar, Tsviqa Lakrec, and Ran Tessler present: The Amplituhedron BCFW Triangulation

There is a recent breakthrough paper The Amplituhedron BCFW Triangulation by Chaim Even-Zohar, Tsviqa Lakrec, and Ran Tessler Abstract:  The amplituhedron   is a geometric object, introduced by Arkani-Hamed and Trnka (2013) in the study of scattering amplitudes in quantum … Continue reading

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Reflections: On the Occasion of Ron Adin’s and Yuval Roichman’s Birthdays, and FPSAC 2021

Two hybrid conferences, Bar-Ilan University:Monday, January 10,2022 10:00-16:00 (Israel time) Reflections: On the occasion of Ron Adin’s and Yuval Roichman’s 60th Birthdays. FPSAC 2021 Starting  Monday, January 10,2022 16:30 (Israel time). Ending Thursday, January 20, 2022.

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Test your intuition 47: AGC-GTC-TGC-GTC-TGC-GAC-GATC-? what comes next in the sequence?

Before getting to the main topic of this post, first, Happy New Year 2022 and Merry Christmas to all readers, and second, a quick update: A community blog to discuss open problems in algebraic combinatorics was created. Everybody is invited … Continue reading

Posted in Algebra, Combinatorics, Geometry, Test your intuition | Tagged , | 1 Comment