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 AlexFest: 60 Faces of Groups
 Postoctoral Positions with Karim and Other Announcements!
 Jirka
 AviFest, AviStories and Amazing Cash Prizes.
 Polymath 10 post 6: The ErdosRado sunflower conjecture, and the Turan (4,3) problem: homological approaches.
 Polymath 10 Emergency Post 5: The ErdosSzemeredi Sunflower Conjecture is Now Proven.
 Mind Boggling: Following the work of Croot, Lev, and Pach, Jordan Ellenberg settled the cap set problem!
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 The Erdős Szekeres polygon problem – Solved asymptotically by Andrew Suk.
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 Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
 A Breakthrough by Maryna Viazovska Leading to the Long Awaited Solutions for the Densest Packing Problem in Dimensions 8 and 24
 Extremal Combinatorics IV: Shifting
 The Simplex, the Cyclic polytope, the Positroidron, the Amplituhedron, and Beyond
 When It Rains It Pours
 Polymath10: The Erdos Rado Delta System Conjecture
 AviFest, AviStories and Amazing Cash Prizes.
 Believing that the Earth is Round When it Matters
 Impagliazzo's Multiverse
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Monthly Archives: May 2009
Some Philosophy of Science
The Bayesian approach to the philosophy of science was developed in the first half of the twentieth century. Karl Popper and Thomas Kuhn are twentiethcentury philosophers of science who later proposed alternative approaches. It will be convenient to start with … Continue reading
Posted in Philosophy, Probability
14 Comments
A Workshop for Advanced Undergraduate Students, Sept 617 2009
סדנא לתלמידי בוגר מצטיינים במתמטיקה מכון איינשטיין למתמטיקה, האוניברסיטה העברית בירושלים יום א’ י”ז אלול – יום ה’ כ”ח אלול תשס”ט 617/9/09 המכון למתמטיקה של האוניברסיטה העברית מזמין תלמידי מתמטיקה מצטיינים המסיימים שנה ב’ או ג’ של … Continue reading
Posted in Uncategorized
1 Comment
Answer to Test Your Intuition (3)
Question: Let be the dimensional cube. Turn into a torus by identifying opposite facets. What is the minumum dimensional volume of a subset of which intersects every nontrivial cycle in . Answer: Taking to be all points in the solid … Continue reading
How Large can a Spherical Set Without Two Orthogonal Vectors Be?
The problem Witsenhausen’s Problem (1974): Let be a measurable subset of the dimensional sphere . Suppose that does not contain two orthogonal vectors. How large can the dimensional volume of be? A Conjecture Conjecture: The maximum volume is attained … Continue reading
Posted in Open problems
4 Comments
Extremal Combinatorics VI: The FranklWilson Theorem
Rick Wilson The FranklWilson theorem is a remarkable theorem with many amazing applications. It has several proofs, all based on linear algebra methods (also referred to as dimension arguments). The original proof is based on a careful study of incidence … Continue reading
Recent and Future Excitements
It is very hectic around here and on top of the eight or so regular research seminars at math (and quite a few more at CS) we have many visitors as school terms at the US are over. A week … Continue reading
Posted in Updates
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The CapSet Problem and FranklRodl Theorem (C)
Update: This is a third of three posts (part I, part II) proposing some extensions of the cap set problem and some connections with the Frankl Rodl theorem. Here is a post presenting the problem on Terry Tao’s blog (March 2007). Here … Continue reading
Posted in Combinatorics, Open problems
Tagged Cap sets, FranklRodl theorem, polymath1
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Ehud Friedgut: Murphy’s Law of Breastfeeding Twins
This post is authored by Ehud Friedgut. Congratulations to Keren, Ehud and Michal for the birth of Shiri and Hillel! Murphy’s law of breastfeeding twins, like all of Murphy’s laws, is supported by strong empirical evidence. The twins’ feeding rhythm … Continue reading
Posted in Guest blogger
9 Comments
The AmitsurLevitzki Theorem for a Non Mathematician.
Yaacov Levitzki The purpose of this post is to describe the AmitsurLevitzki theorem: It is meant for people who are not necessarily mathematicians. Yet they need to know two things. The first is what matrices are. Very briefly, matrices are rectangular arrays … Continue reading
Posted in Algebra and Number Theory
Tagged Alex Levitzki. Yaacov Levitzki, Shimshon Amitsur
7 Comments