### Recent Comments

Gil Kalai on זה הזמן לשינוי קוסמופוליט on זה הזמן לשינוי Gil Kalai on זה הזמן לשינוי Eli_B on זה הזמן לשינוי Michael Elkin on זה הזמן לשינוי Gil Kalai on זה הזמן לשינוי Eli_B on זה הזמן לשינוי Gil Kalai on זה הזמן לשינוי Gil Kalai on זה הזמן לשינוי Eli_B on זה הזמן לשינוי Gil Kalai on זה הזמן לשינוי Michael Elkin on זה הזמן לשינוי -
### Recent Posts

- זה הזמן לשינוי
- Combinatorics and More – Greatest Hits
- Ilan and me
- The Simplex, the Cyclic polytope, the Positroidron, the Amplituhedron, and Beyond
- From Oberwolfach: The Topological Tverberg Conjecture is False
- Midrasha Mathematicae #18: In And Around Combinatorics
- Quantum computing: achievable reality or unrealistic dream
- A Historical Picture Taken by Nimrod Megiddo
- Scott Triumphs* at the Shtetl

### Top Posts & Pages

- זה הזמן לשינוי
- Combinatorics and More - Greatest Hits
- Believing that the Earth is Round When it Matters
- The Kadison-Singer Conjecture has beed Proved by Adam Marcus, Dan Spielman, and Nikhil Srivastava
- Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
- Extremal Combinatorics I: Extremal Problems on Set Systems
- Academic Degrees and Sex
- Happy Birthday Richard Stanley!
- Quantum computing: achievable reality or unrealistic dream

### RSS

# Monthly Archives: April 2012

## A Really Nice Talk About PDE, Numerics (and Pyramids)

My previous post recommended a really nice talk by Jonathan Israel about human rights. Here is the link again. It is very recommended. Actually, I was in the audience and after the lecture, at the reception, I came to the … Continue reading

Posted in Analysis, Applied mathematics
1 Comment

## The 1789 Declaration of the Rights of Man

Today (April 27, 2012) it is precisely 213 years 7 months, and 29 days to the completion of the declaration of the rights of man, which makes it a perfect occasion to celebrate this remarkable human creation. Here is a … Continue reading

## Galvin’s Proof of Dinitz’s Conjecture

Dinitz’ conjecture The following theorem was conjectured by Jeff Dinitz in 1979 and proved by Fred Galvin in 1994: Theorem: Consider an n by n square table such that in each cell (i,j) you have a set with n or more elements. … Continue reading

Posted in Combinatorics, Games
4 Comments

## Greg Kuperberg: It is in NP to Tell if a Knot is Knotted! (under GRH!)

Wolfgang Haken found an algorithm to tell if a knot is trivial, and, more generally with Hemion, if two knots are equivalent. Joel Hass, Jeff Lagarias and Nick Pippinger proved in 1999 that telling that a knot is unknotted is … Continue reading

## Exciting News on Three Dimensional Manifolds

The Virtually Haken Conjecture A Haken 3-manifold is a compact 3-dimensional manifold M which is irreducible (in a certain strong sense) but contains an incompressible surface S. (An embedded surface S is incompressible if the embedding indices an injection of its … Continue reading