### Recent Comments

dinostraurio on Seven Problems Around Tverberg… Matthew Cory on The Quantum Computer Puzzle @… Matthew Cory on The Quantum Computer Puzzle @… The Quantum Computer… on A Breakthrough by Maryna Viazo… The Quantum Computer… on Stefan Steinerberger: The Ulam… The Quantum Computer… on Polymath10-post 4: Back to the… Philip Gibbs on Stefan Steinerberger: The Ulam… Philip Gibbs on Stefan Steinerberger: The Ulam… Daniel on Stefan Steinerberger: The Ulam… Philip Gibbs on Stefan Steinerberger: The Ulam… Gil Kalai on Stefan Steinerberger: The Ulam… Gabriel Nivasch on Stefan Steinerberger: The Ulam… -
### Recent Posts

- The Quantum Computer Puzzle @ Notices of the AMS
- Three Conferences: Joel Spencer, April 29-30, Courant; Joel Hass May 20-22, Berkeley, Jean Bourgain May 21-24, IAS, Princeton
- Math and Physics Activities at HUJI
- Stefan Steinerberger: The Ulam Sequence
- TYI 26: Attaining the Maximum
- A Breakthrough by Maryna Viazovska Leading to the Long Awaited Solutions for the Densest Packing Problem in Dimensions 8 and 24
- Polymath10-post 4: Back to the drawing board?
- News (mainly polymath related)
- Polymath 10 Post 3: How are we doing?

### Top Posts & Pages

- A Breakthrough by Maryna Viazovska Leading to the Long Awaited Solutions for the Densest Packing Problem in Dimensions 8 and 24
- Stefan Steinerberger: The Ulam Sequence
- The Quantum Computer Puzzle @ Notices of the AMS
- Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
- Three Conferences: Joel Spencer, April 29-30, Courant; Joel Hass May 20-22, Berkeley, Jean Bourgain May 21-24, IAS, Princeton
- Polymath10-post 4: Back to the drawing board?
- When It Rains It Pours
- Aaronson and Arkhipov's Result on Hierarchy Collapse
- Believing that the Earth is Round When it Matters

### RSS

# Monthly Archives: September 2013

## Real Analysis Introductory Mini-courses at Simons Institute

The Real Analysis ‘Boot Camp’ included three excellent mini-courses. Inapproximability of Constraint Satisfaction Problems (5 lectures) Johan Håstad (KTH Royal Institute of Technology) (Lecture I, Lecture II, Lecture III, Lecture IV, Lecture V) Unlike more traditional ‘boot camps’ Johan rewarded answers and questions … Continue reading

## Analysis of Boolean Functions – week 4

Lecture 6 Last week we discussed two applications of the Fourier-Walsh plus hypercontractivity method and in this lecture we will discuss one additional application: The lecture was based on a 5-pages paper by Ehud Friedgut and Jeff Kahn: On the number … Continue reading

## Polymath 8 – a Success!

Yitang Zhang Update (July 22, ’14). The polymath8b paper “Variants of the Selberg sieve, and bounded intervals containing many primes“, is now on the arXiv. See also this post on Terry Tao’s blog. Since the last update, we also had here … Continue reading

## Analysis of Boolean Functions – Week 3

Lecture 4 In the third week we moved directly to the course’s “punchline” – the use of Fourier-Walsh expansion of Boolean functions and the use of Hypercontractivity. Before that we started with a very nice discrete isoperimetric question on a … Continue reading

## Richard Stanley: How the Proof of the Upper Bound Theorem (for spheres) was Found

The upper bound theorem asserts that among all d-dimensional polytopes with n vertices, the cyclic polytope maximizes the number of facets (and k-faces for every k). It was proved by McMullen for polytopes in 1970, and by Stanley for general triangulations … Continue reading

## Simons@UCBerkeley

Raghu Meka talking at the workshop I spend the semester in Berkeley at the newly founded Simons Institute for the Theory of Computing. The first two programs demonstrate well the scope of the center and why it is needed. One program … Continue reading

Posted in Conferences, Updates
1 Comment

## Analysis of Boolean functions – week 2

Post on week 1; home page of the course analysis of Boolean functions Lecture II: We discussed two important examples that were introduced by Ben-Or and Linial: Recursive majority and tribes. Recursive majority (RM): is a Boolean function with variables … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Probability, Teaching
Tagged Boolean functions, Tribes
Leave a comment

## Around Borsuk’s Conjecture 3: How to Save Borsuk’s conjecture

Borsuk asked in 1933 if every bounded set K of diameter 1 in can be covered by d+1 sets of smaller diameter. A positive answer was referred to as the “Borsuk Conjecture,” and it was disproved by Jeff Kahn and me in 1993. … Continue reading

## Analysis of Boolean Functions – week 1

Home page of the course. In the first lecture I defined the discrete n-dimensional cube and Boolean functions. Then I moved to discuss five problems in extremal combinatorics dealing with intersecting families of sets. 1) The largest possible intersecting family … Continue reading