The Hadwiger-Nelson problem is that of determining the chromatic number of the plane (), defined as the minimum number of colours that can be assigned to the points of the plane so as to prevent any two points unit distance apart from being the same colour. 220 more words

## Tags » Polymath Proposals

#### A new polymath proposal (related to the Riemann Hypothesis) over Tao's blog

(From a post “the music of the primes” by Marcus du Sautoy.)

A new polymath proposal over Terry Tao’s blog who wrote: “Building on the interest expressed in the comments to 90 more words

#### Spontaneous Polymath 14 - A success!

This post is to report an unplanned polymath project, now called polymath 14 that took place over Terry Tao’s blog. A problem was posed by Apoorva Khare was presented and discussed… 9 more words

#### Polymath 13 - a success!

This post is to note that the polymath13 project has successfully settled one of the major objective. Reports on it can be found on Gower’s blog especially in this post 26 more words

#### Non-transitive Dice over Gowers's Blog

A polymath-style project on non transitive dice (Wikipedea) is now running over Gowers blog. (Here is the link to the first post.)

#### Rota's Basis Conjecture: Polymath 12, post 3

We haven’t quite hit the 100-comment mark on the second Polymath 12 blog post, but this seems like a good moment to take stock. The project has lost some of its initial momentum, perhaps because other priorities have intruded into the lives of the main participants (I know that this is true of myself). 1,125 more words