Category Archives: Geometry

Interesting Times in Mathematics: Enumeration Without Numbers, Group Theory Without Groups.

Lie Theory without Groups: Enumerative Geometry and Quantization of Symplectic Resolutions Our 21th Midrasha (school) IIAS, January 7 – January 12, 2018 Jerusalem Enumerative Geometry Beyond Numbers MSRI,  January 16, 2018 to May 25, 2018 Abstract for the Midrasha Advertisements

Posted in Algebra and Number Theory, Combinatorics, Geometry, Updates | Leave a comment

High Dimensional Combinatorics at the IIAS – Program Starts this Week; My course on Helly-type theorems; A workshop in Sde Boker

The academic year starts today. As usual it is very hectic and it is wonderful to see the ever younger and younger students. Being a TelAvivian in residence in the last few years, I plan this year to split my … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Geometry, Updates | Tagged , , | 4 Comments

Stan Wagon, TYI 23: Ladies and Gentlemen: The Answer

TYI 32, kindly offered by Stan Wagon asked A round cake has icing on the top but not the bottom. Cut out a piece in the usual shape (a sector of a circle with vertex at the center), remove it, … Continue reading

Posted in Combinatorics, Geometry, Test your intuition | Tagged , | 8 Comments

The World of Michael Burt: When Architecture, Mathematics, and Art meet.

  This remarkable 3D geometric object tiles space! It is related to a theory of “spacial networks” extensively studied by Michael Burt and a few of his students. The network associated to this object is described in the picture below. … Continue reading

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Micha Perles’ Geometric Proof of the Erdos-Sos Conjecture for Caterpillars

A geometric graph is a set of points in the plane (vertices) and a set of line segments between certain pairs of points (edges). A geometric graph is simple if the intersection of  two edges is empty or a vertex … Continue reading

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Touching Simplices and Polytopes: Perles’ argument

Joseph Zaks (1984), picture taken by Ludwig Danzer (OberWolfach photo collection)   The story I am going to tell here was told in several places, but it might be new to some readers and I will mention my own angle, … Continue reading

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Jozsef Solymosi is Giving the 2017 Erdős Lectures in Discrete Mathematics and Theoretical Computer Science

                            May 4 2:30-3:30; May 7 11:00-13:00; May 10 10:30-12:00 See the event webpage for titles and abstracts (or click on the picture below).  

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Around the Garsia-Stanley’s Partitioning Conjecture

  Art Duval, Bennet Goeckner, Carly Klivans, and Jeremy Martin found a counter example to the Garsia-Stanley partitioning conjecture for Cohen-Macaulay complexes. (We mentioned the conjecture here.)  Congratulations Art, Bennet, Carly and Jeremy!  Art, Carly, and Jeremy also wrote an article on the … Continue reading

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The Mathematics of Jiří Matoušek is a conference taking place this week at Prague in memory of Jirka Matoušek.  Here are the slides of my planned talk on Maestro Jirka Matoušek. This post presents the opening slides for the conference … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Conferences, Geometry, Obituary | Tagged | 4 Comments

The Erdős Szekeres polygon problem – Solved asymptotically by Andrew Suk.

Here is the abstract of a recent paper by Andrew Suk. (I heard about it from a Facebook post by Yufei Zhao. I added a link to the original Erdős Szekeres’s paper.) Let ES(n) be the smallest integer such that … Continue reading

Posted in Combinatorics, Geometry, Updates | Tagged | 2 Comments