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- New Ramanujan Graphs!
- Amazing: Peter Keevash Constructed General Steiner Systems and Designs
- Can Category Theory Serve as the Foundation of Mathematics?
- Why is Mathematics Possible: Tim Gowers's Take on the Matter
- Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun

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# Monthly Archives: January 2012

## Fractional Sylvester-Gallai

Avi Wigderson was in town and gave a beautiful talk about an extension of Sylvester-Gallai theorem. Here is a link to the paper: Rank bounds for design matrices with applications to combinatorial geometry and locally correctable codes by Boaz Barak, Zeev … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Geometry
Tagged Avi Wigderson, Codes, Greg Kuperberg, Sylvester-Gallai
4 Comments

## A Theorem About Infinite Cardinals Everybody Should Know

Cantor proved and we all know that for every cardinal we have This is a very basic fact about cardinal arithmetic and it is nice that the proof works for finite and infinite cardinals equally well. (For the finite case it … Continue reading