Category Archives: Computer Science and Optimization

Günter Ziegler: 1000$ from Beverly Hills for a Math Problem. (IPAM remote blogging.)

Scanned letter by Zadeh. (c) Günter M. Ziegler left-to-right: David Avis, Norman Zadeh,  Oliver Friedmann, and Russ Caflish (IPAM director). Photo courtesy Eddie Kim. Update: The slides for Friedmann’s talk are now available. The conference schedule page contains now the slides for … Continue reading

Posted in Computer Science and Optimization, Conferences, Guest blogger | Tagged | 4 Comments

IPAM Remote Blogging: Santos-Weibel 25-Vertices Prismatoid and Prismatoids with large Width

Here is a web page by Christope Weibel on the improved counterexample. The IPAM webpage contains now slides of some of the lectures. Here are Santos’s slides. The last section contains some recent results on the “width of 5-prismatoids”  A prismatoid is a polytope … Continue reading

Posted in Computer Science and Optimization, Conferences, Convex polytopes | 2 Comments

Remote Blogging: Efficiency of the Simplex Method: Quo vadis Hirsch conjecture?

Here are some links and posts related to some of the talks in IPAM’s workshop “Efficiency of the Simplex Method: Quo vadis Hirsch conjecture?” I will be happy to add links to pdf’s of the presentations and to relevant papers. Descriptions and … Continue reading

Posted in Computer Science and Optimization, Conferences, Convex polytopes | 3 Comments

Is Backgammon in P?

  The Complexity of Zero-Sum Stochastic Games with Perfect Information Is there a polynomial time algorithm for chess?  Well, if we consider the complexity of chess in terms of the board size then it is fair to think that the answer is … Continue reading

Posted in Computer Science and Optimization, Games, Open problems, Probability | 9 Comments

To Life, to Science and to Innovations

ICS2011 at ITCS, Tsinghua University, Beijing, China The title of this post “To life, to Science and to Innovations” was Silvio Micali’s toast at the second conference on Innovations in Computer Science and Silvio’s words have a good chance of becomeing the official toast of … Continue reading

Posted in Computer Science and Optimization, Conferences | 7 Comments

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

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

Posted in Computer Science and Optimization, Physics | Tagged , , , , , | 10 Comments

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

Posted in Algebra and Number Theory, Combinatorics, Computer Science and Optimization, Open problems, Physics | Tagged , , , | 11 Comments

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

Posted in Computer Science and Optimization, Convex polytopes, Games | Tagged , | 11 Comments

IPAM Workshop – Efficiency of the Simplex Method: Quo vadis Hirsch conjecture?

  Workshop at IPAM: January 18 – 21, 2011 Here is the link to the IPAM conference. 

Posted in Combinatorics, Computer Science and Optimization, Conferences, Convex polytopes | Leave a comment