Here are three things we noticed this month which didn’t get a proper write-up, due to thesis/Edinburgh fringe/holidays: a big proof, a fun maths book club, and a ridiculous bit of pi-related madhattery.

### Kadison-Singer conjecture proved

Adam Marcus and Daniel Spielman from Yale, with Nikhil Srivastava of Microsoft Research India, have announced a proof of the Kadison-Singer conjecture. There’s no Wikipedia entry for the conjecture, although Richard Kadison’s page and a paper I found seem to suggest it’s something to do with operator algebras – and the MAA news article through which we found the announcement states that the result “has consequences for the foundations of physics”.

**Source:** Kadison-Singer conjecture succumbs to proof, at MAA Maths News.

**Paper: **Interlacing Families II: Mixed Characteristic Polynomials and the Kadison-Singer Problem at the arXiv.

### Maths Book Club

If you’re sick of Richard and Judy telling you what to read and when, and you’d much rather read maths books anyway, there’s a new book club which you’d surely prefer. Run by Hannah, who co-organises Leeds MathsJam, the Maths Book Club aims to coordinate a group of people reading maths books and then discussing them via Twitter. Their first book, as voted for on their website, is Alex Bellos’ *Alex’s Adventures in Numberland*, which you’re required to read by **Wednesday 23rd October**, and then join in with the Twitter chat thereon.

**More details:**

Maths Book Club website

@MathsBookClub on Twitter

### Revolutionary π file storage system

Worried about soaring costs for storing your data? No longer! GitHub user Philip Langdale has come up with a fantastic way to achieve that elusive 100% compression. The theory: any string of data you might wish to store already exists somewhere in the digits of π (provided, of course, we can prove it’s a normal number, as has long been suspected). So instead of using up precious storage space, simply record the starting digit and length of your string in the digits of π, and when you need to retrieve it, all you need to do is calculate the relevant digits using mathematical principles. It’s genius!

**Source:** πfs – the data-free filesystem! on GitHub.

I liked this issue from πfs: https://github.com/philipl/pifs/issues/2

For Item 1, see also http://aperiodical.com/2013/07/not-mentioned-recently-on-the-aperiodical/ :)

Hah, well spotted! I thought I’d already covered it…