Author Archives: Gil Kalai

Scott Triumphs* at the Shtetl

Scott Aaronson wrote a new post on the Shtetl Optimized** reflecting on the previous thread  (that I referred to in my post on Amy’s triumph), and on reactions to this thread. The highlight is a list of nine of Scott’s … Continue reading

Posted in Updates, Women in science | Tagged , | 6 Comments

Amy Triumphs* at the Shtetl

It was not until the 144th comment by a participants named Amy on Scott’s Aaronson recent Shtetl-optimized** post devoted to a certain case of sexual harassment at M. I. T. that the discussion turned into something quite special. Amy’s great … Continue reading

Posted in Controversies and debates, Women in science | Tagged , , | 23 Comments


Ilya Rips and me during Ilyafest last week (picture Itai Benjamini) Ilya Rips Birthday Conference Last week we had here a celebration for Ilya Rips’ birthday. Ilya is an extraordinary mathematician with immense influence on algebra and topology. There were … Continue reading

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When Do a Few Colors Suffice?

When can we properly color the vertices of a graph with a few colors? This is a notoriously difficult problem. Things get a little better if we consider simultaneously a graph together with all its induced subgraphs. Recall that an … Continue reading

Posted in Combinatorics | Tagged | 1 Comment

From Peter Cameron’s Blog: The symmetric group 3: Automorphisms

Originally posted on Peter Cameron's Blog:
No account of the symmetric group can be complete without mentioning the remarkable fact that the symmetric group of degree n (finite or infinite) has an outer automorphism if and only if n=6.…

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Coloring Simple Polytopes and Triangulations

Coloring Edge-coloring of simple polytopes One of the equivalent formulation of the four-color theorem asserts that: Theorem (4CT) : Every cubic bridgeless planar graph is 3-edge colorable So we can color the edges by three colors such that every two … Continue reading

Posted in Combinatorics, Open problems | Tagged , | 10 Comments

TYI 25: The Automorphism Group of the Symmetric Group

True or False: The group of automorphisms of the symmetric group , n ≥ 3 is itself.  

Posted in Algebra and Number Theory, Test your intuition | Tagged , | 7 Comments

Test your intuition 24: Which of the following three groups is trivial

Martin Bridson We have three finitely presented groups A is generated by two generators a and b and one relation   B is generated by three generators a, b, c and three relations ,    . C is generated by four generators a, b, c, d … Continue reading

Posted in Algebra and Number Theory, Test your intuition | Tagged , | 10 Comments

School Starts at HUJI

We are now starting the third week of the academic year at HUJI. As usual, things are very hectic, a lot of activities in the mathematics department, in our sister CS department, around in the campus, and in our combinatorics … Continue reading

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A lecture by Noga

Noga with Uri Feige among various other heroes A few weeks ago I devoted a post to the 240-summit conference for Péter Frankl, Zoltán Füredi, Ervin Győri and János Pach, and today I will bring you the slides of Noga … Continue reading

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