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Monthly Archives: November 2010
Polynomial Hirsch Conjecture 5: Abstractions and Counterexamples.
This is the 5th research thread of polymath3 studying the polynomial Hirsch conjecture. As you may remember, we are mainly interested in an abstract form of the problem about families of sets. (And a related version about families of multisets.) The … Continue reading
Analysis of Boolean Functions
I discovered a vidiotaped lecture I gave at the Open University on the 3rd Israeli Theory Day. Enjoy! http://www.youtube.com/watch?v=xbJe7ioCISM Posts related to this lecture: Noise Stability and threshold circuits; Noise stability lecture and tales; Nati’s influence.
Posted in Computer Science and Optimization
3 Comments
Emmanuel Abbe: Erdal Arıkan’s Polar Codes
Click here for the most recent polymath3 research thread. A new thread is comming soon. Emmanuel Abbe and Erdal Arıkan This post is authored by Emmanuel Abbe A new class of codes, called polar codes, recently made a breakthrough in … Continue reading
Roth’s Theorem: Tom Sanders Reaches the Logarithmic Barrier
Click here for the most recent polymath3 research thread. I missed Tom by a few minutes at Mittag-Leffler Institute a year and a half ago Suppose that is a subset of of maximum cardinality not containing an arithmetic progression of length 3. Let . … Continue reading
Posted in Combinatorics, Open problems
Tagged Endre Szemeredi, Jean Bourgain, Klaus Roth, Roger Heath-Brown, Roth's theorem, Tom Sanders
12 Comments
János Pach: Guth and Katz’s Solution of Erdős’s Distinct Distances Problem
Click here for the most recent polymath3 research thread. Erdős and Pach celebrating another November day many years ago. The Wolf disguised as Little Red Riding Hood. Pach disguised as another Pach. This post is authored by János Pach A … Continue reading
Posted in Combinatorics, Geometry, Guest blogger, Open problems
Tagged Larry Guth, Nets Hawk Katz
13 Comments
Aaronson and Arkhipov’s Result on Hierarchy Collapse
Scott Aaronson gave a thought-provoking lecture in our Theory seminar three weeks ago. (Actually, this was eleven months ago.) The slides are here . The lecture discussed two results regarding the computational power of quantum computers. One result from this paper gives an … Continue reading
Octonions to the Rescue
Xavier Dahan and Jean-Pierre Tillich’s Octonion-based Ramanujan Graphs with High Girth. Update (February 2012): Non associative computations can be trickier than we expect. Unfortunately, the paper by Dahan and Tillich turned out to be incorrect. Update: There is more to … Continue reading
Subexponential Lower Bound for Randomized Pivot Rules!
Oliver Friedmann, Thomas Dueholm Hansen, and Uri Zwick have managed to prove subexponential lower bounds of the form for the following two basic randomized pivot rules for the simplex algorithm! This is the first result of its kind and deciding … Continue reading
Combinatorics and more 