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“π – It’s Complicated” – a talk I gave on Pi Day 2016 at Ustinov College Café Scientifique

I was invited to give a talk for Ustinov College’s Café Scientifique on π Day this year. The turnout wasn’t great and I put quite a bit of effort into the slides, so I wanted to put it online. I’ve finally got hold of the recording, so here it is. Unfortunately they didn’t set the camera’s exposure properly, making the screen illegible, so you’ll probably want to follow along with the slides in another window.

I tried to come up with a way of writing today’s date as a multiple of π Day, but couldn’t make it work. However, I did realise that Halloween (31/10) is the best approximation to π between now and the next π day (I think). Sπooky!

The world’s smallest Rubik’s cube is 5.6mm wide and absolutely adorable

I just found this video of a very focused man showing off a teeny tiny Rubik’s cube. It’s 5.6mm on each side, which apparently makes it the smallest in the world, beating some relatively gigantesque efforts of 6mm and larger.

Watch this video; I’ll warn you now that the squee factor gives way to some very dry detail quite quickly.

The cube was made by Tony Fisher, by filing down a 3D-printed 6mm cube. I hadn’t heard of Tony before, which surprises me – his site is full of all sorts of incredible twisty puzzles.

The University of Leicester is going to sack its whole maths department (and rehire some of them)


The University of Leicester says it’s facing a big budget deficit, so it’s got to make some cuts. In the current British climate, that’s nothing unusual. However, the university has decided to cut a lot more from the maths department than elsewhere.

The way they’re going to do this is to sack almost everyone, then ask them to re-apply for slightly fewer jobs than there were before. Once it’s all done, 6 of the 21 mathematicians currently working at Leicester will be out of a job.

There’s some speculation that the reason that maths is going to be hit particularly hard is that it didn’t do particularly well in the last iterations of the REF and the National Student Survey.

The Universities and Colleges Union has started a petition against the cuts, disputing the size of the deficit and the need for so many job losses. They’ve written a response laying out their side of the story. The European Mathematical Society has also said it’s very concerned.

Tim Gowers has written a bit more about what he thinks is going on on his blog. As usual, there’s some good discussion in the comments as well.

via Yemon Choi

Do you use mixed fractions?

I’m at the MATRIX conference in Leeds, where I’ve just been talking to Adam Atkinson. He told me that he’s trying to compile a definitive list of countries that don’t use mixed fractions.

Here’s a mixed fraction: \[ 2 \frac{2}{3} \]
And here’s a non-mixed fraction: \[ \frac{8}{3} \]
Actually, here’s an interesting fact about that number: \[ 2 \sqrt{ \frac{2}{3} } = \sqrt{ 2 \frac{2}{3} } \]
This only makes sense if you believe in mixed fractions (and unicode character U+2062, “invisible times”)

This is going to be one of those wipe-your-bum-standing-up situations: it’s entirely possible that you can be on either side of this divide and not know the other exists. Apparently, in some countries mixed fractions just don’t exist: an integer written next to a fraction is incorrect.

So, to help Adam on his way, I thought I’d start another in our long-running series of Aperiodical Surveys. Please tell us where you live, and if mixed fractions are OK in your book.

Integer Sequence Reviews: A075771, A032799, A002717

It’s been almost two years since I last sat down with my friend David Cushing and did what God put us on this Earth to do: review integer sequences.

This week I lured David into my office with promises of tasty food and showed him some sequences I’d found. Thanks to (and also in spite of) my Windows 10 laptop, the whole thing was recorded for your enjoyment. Here it is:

I can only apologise for the terrible quality of the video – I was only planning on using it as a reminder when I did a write-up, but once we’d finished I decided to just upload it to YouTube and be done with it.

New MathJax accessibility extensions provide collapsible expressions and maths-to-speech

MathJax, the web library that provides LaTeX-quality mathematical typesetting, has received a a new set of tools to improve accessibility of mathematical notation. The new MathJax Accessibility Extensions add on-the-fly speech rendering of notation, and a tool to explore expressions through intelligent collapsing and expanding of sub-expressions.