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 Past and Future Events
 Joshua Hinman proved Bárány’s conjecture on face numbers of polytopes, and Lei Xue proved a lower bound conjecture by Grünbaum.
 Amazing: Jinyoung Park and Huy Tuan Pham settled the expectation threshold conjecture!
 Combinatorial Convexity: A Wonderful New Book by Imre Bárány
 Chaim EvenZohar, Tsviqa Lakrec, and Ran Tessler present: The Amplituhedron BCFW Triangulation
 Ehud Friedgut: How many cubes of 2×2×2 fit into a box of size 8×4×3? (TYI 49)
 Is HQCA Possible? A conversation with Michael Brooks
 To cheer you up in difficult times 35 combined with Test Your Intuition 48: Alef’s corner – Jazz and Math
 Reflections: On the Occasion of Ron Adin’s and Yuval Roichman’s Birthdays, and FPSAC 2021
Top Posts & Pages
 Amazing: Jinyoung Park and Huy Tuan Pham settled the expectation threshold conjecture!
 Joshua Hinman proved Bárány's conjecture on face numbers of polytopes, and Lei Xue proved a lower bound conjecture by Grünbaum.
 TYI 30: Expected number of Dice throws
 Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
 Game Theory 2021
 Telling a Simple Polytope From its Graph
 A sensation in the morning news  Yaroslav Shitov: Counterexamples to Hedetniemi's conjecture.
 Bálint Virág: Random matrices for Russ
 Past and Future Events
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Monthly Archives: February 2009
Ziegler´s Lecture on the Associahedron
The associahedron in 3 dimension, and James Stasheff. This picture is taken from Bill Casselman’s article on the associahedron. The article is entitled “Strange Associations” and starts with “There are many other polytopes that can be described in purely combinatorial terms. Among the … Continue reading
Posted in Convex polytopes
Tagged Associahedron, Cyclohedron, Permutahedron, Permutoassociahedron
8 Comments
A Little More on Boolean Functions and Bounded Depth Circuits
Boolean circuits This post (in a few parts) contains a quick introduction to Boolean circuits. It is related to the recent news post about the solution of Braverman to the LinialNisan conjecture. In particular, we will describe very quickly a formulation … Continue reading
Posted in Computer Science and Optimization
7 Comments
Rosenfeld’s OddDistance Problem
Moshe Rosenfeld’s odddistance problem: Let G be the graph whose vertices are points in the plane and two vertices form an edge if their distance is an odd integer. Is the chromatic number of this graph finite?
Posted in Combinatorics, Open problems
3 Comments
Which Coalition to Form (2)?
Yair Tauman (This post is a continuation of this previous post.) Aumann and Myerson proposed that if political and ideological matters are put aside, the party forming the coalition would (or should) prefer to form the coalition in which its own power (according … Continue reading
Which Coalition?
The problem. OK, we had an election and have a new parliament with 120 members. The president has asked the leader of one party to form a coalition. (This has not happened yet in the Israeli election but it will happen soon.) Such … Continue reading
Basic Open Research and Failed Institutions – Imagine
Imagine if in the last ten years before the collapse, the huge failed financial and insurance institutions had had independent research units devoted to doing basic, open, and critical research on matters of relevance to the business, ethics, and future of these institutions. Might it have made a small … Continue reading
Majority Rules! – The Story of Achnai’s Oven
It is election day in Israel, and an opportunity to tell the beautiful and moving story of Achnai’s oven. Towards the end of the first century, a few decades after the big Jewish rebellion against the Romans, the sages of the … Continue reading
Posted in Rationality
13 Comments
FranklRodl’s Theorem and Variations on the Cap Set Problem: A Recent Research Project with Roy Meshulam (A)
Voita Rodl I would like to tell you about a research project in progress with Roy Meshulam. (We started it in the summer, but then moved to other things; so far there are interesting insights, and perhaps problems, but not substantial … Continue reading
Posted in Combinatorics, Open problems
Tagged Cap sets, Extremal combinatorics, Intersection theorems, polymath1
10 Comments
Colloquium at Berlin
I arrived to Berlin for a short visit to give a colloquium talk at the new BMS on Hellytype theorems, and to participate in the Ph. D. committee of Ronald Wotzlaw. (Update: Dr. Ronald Wotzlaw.) Here is an abstract for the … Continue reading
Posted in Convexity, Updates
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The HexVotingRule (Not Recommended)
Blue wins – if there is a right to left continuous path of blue regions Red wins – if there is north to south continuous path of red regions (A region is red or blue according to the majority of … Continue reading
Posted in Economics, Games
13 Comments