1 What

This is a place for me to either post or link to things that I've written, mainly about Mathematics and Programming.

2 Why

I write things for two reasons: to stop thinking about it or to stop talking about it.

When an idea is only in my head, it is still very malleable. This has the side effect that I continually return to it to see if my thinking about it has changed, or to see if there is some aspect that I have overlooked. The act of writing it serves as a crystallisation process, particularly if I can pretend that I am writing for others to see. Once it is written, I no longer have to hold it in my head and can therefore think about other things safe in the knowledge that if I want to think about it again then I can do so.

With some topics, I find myself saying the same thing time and time again. For these, I like to be able to point to a place where I've written it down. Not only does this save me from repeating myself, but it also ensures that I can say all that I want to say on a particular topic without feeling as though I'm overwhelming whoever I'm talking to.

3 Who

When I started this website, I decided to write it pseudonymously. At the time I was changing career – from an academic to a teacher – and I wasn't sure how my online presence would work in the new setting. As an academic Mathematician, I had been quite vocal online and I felt that I should draw a line under that. So I changed my username on all my accounts and made this website pseudonymous.

I originally explained this thusly:

This website is written pseudonomously. It is not anonymous, it's not hard to work out who I am, but my intention is that what I write should stand on its own and not gain its import from who wrote it. I've also not given a direct way to contact me. For some things there are standard ways (such as via bug trackers). For others, if you really want to contact me about it then I'm sure you'll figure it out. If you can't, you obviously didn't really want to contact me after all.

Six years on, I feel that I've fully made the transition to teacher but I have found that I draw considerably on my experience as an academic so it's been at the back of my mind to start using my real name on the internet again.

At time of writing, we're about to enter a bizarre phase in teaching as Covid-19 sweeps across the globe and our classes are going "online". The Mathematics Education community in the UK has a huge online presence and I expect it to be quite an important part of my professional life in the coming months. Although my real name is unlikely to mean any more to anyone than my pseudonymous one, there is a psychological difference in interacting with a weird username and a real name. So it seems an appropriate time to drop the pseudonymous act.

Let me, therefore, introduce myself. I am Andrew Stacey, and I am a Mathematician. Currently a school teacher in Oxford, formerly a University Lecturer in Norway (my appointment there was roughly equivalent to "Associate Professor" in the US or "Reader" in the UK, in that I had tenure and the next promotion would have been to full Professor). You can find out more about my professional activity:

• On Twitter: I regard my activity here as semi-professional. It comes with the standard "opinions my own not my employer's", but I try to stay on topic of Mathematics, broadly interpreted.

• On the arXiv.

• On the nLab: I no longer consider myself part of this community – we parted on good terms! – but it was a huge part of my academic life and I think I can say that I had a considerable influence in the days of its infancy.

• On MathOverflow: I'm not really active on this site anymore (having been one of the first to register) but if you have a question that is directly in my line of expertise feel free to draw my attention to it.

• On TeX-SX: I'm still active here within the bounds that a busy life permits. (I've also participated in a few other of the StackExchange sites, but I won't list them all here.)

• On CTAN: I still find it unreal that I actually have contributed some packages to CTAN.

• On github: it's amazing how much code I write to try to make my life easier. A lot of my code ends up as a webpage and you can find those linked from my code site.

• On the Codea forums: I never realised how much fun programming could be until I encountered Codea on an iPad.

Easiest way to contact me is probably via Twitter, but my email is not hard to figure out: take the domain name of this website and convert it to an email address in the obvious way.

I'm not changing my gravatar picture, though. Not for anonymity, you understand, just vanity.

4 How

Over the years I've experimented with lots of ways of maintaining a website. The system behind this one is a git repository containing LaTeX files in a hierarchy of directories. Each LaTeX file corresponds to one webpage here. They are converted to HTML5+MathML by TeX itself.