# Diversions in Mathematics #1: How to Count like a Pure Mathematician

If you want to know what this is all about, read my introduction to the series.

If you have already read the introduction, then welcome to the first Diversion in Mathematics! I emphasise, as I did in the introduction, that I will write with the general public in mind, so don’t be worried if you don’t consider yourself a “fan” of mathematics, or if you’ve totally suppressed all memories of maths classes from high school. And if you are a keen mathematician, whether recreationally or studying seriously at college/university, hopefully you will also find these blogs to be of some interest.

# Diversions in Mathematics #0

Introduction to the series

I have always been interested in maths, and not only in the subject itself but also the ways in which maths is explained and taught. In general, a crucial part of studying and researching is to be able to communicate one’s findings to other people, who may or may not be knowledgeable in your field. For this reason, I’m all for popular science books and magazines, which (provided that it is done well) serve to explain scientific research in an accessible way, and to promote scientific awareness and appreciation amongst the general public. However, in my opinion, popular science books too often simplify, and even completely skip the mathematics behind the science. There is certainly a cultural aversion to mathematics — at least from my perspective as an Australian, and from my awareness of similar attitudes in the US and UK — which may be part of the reason for the lack of ‘real’ mathematics in popular science writing. Here is an anecdote: apparently Stephen Hawking’s publisher advised the great scientist that every equation he included in his A Brief History of Time would result in reduced sales. (There is one equation though: Einstein’s $E = mc^2$). Of course, this is one of the bestselling science books ever, and sits atop many a coffeetable, but I wonder how many people have seriously read it…

# Composer’s Notebook #3

I haven’t posted written anything here for a long time, since I’m busy with Uni study, but here’s a quick piece!

This is a fascinating video of the 2nd movement of Webern’s Variations. I highly recommend listening to the whole piece — after all, even with all the three movements combined, it’s only 5 minutes long! I want to point out a few important features here.

First of all, when I first came across this piece some years ago, I thought it was very beautiful. In case you’re interested, the recording was by Mitsuko Uchida (the album also features the Schoenberg Piano Concerto). Played by a computer here, it sounds rather ugly to me, which dispels the misconception that somehow serial music is completely emotionless.

Secondly, the binary form of this movement is perfectly visible in this animation, you can even tell where the repeats are! The pitch symmetry is also very clear from the graphics, and we appreciate the almost mathematical precision of the structure.

Thirdly, those of you more familiar with 12-tone music might hear that the harmony is very saturated. I haven’t studied this piece in detail at all, but I think one can discern by ear the inherent symmetries in Webern’s tone row manipulations. Indeed if you look at the score, you will see many palindromic phrases. In order to construct such highly symmetrical music it is necessary to restrict the set of “allowable” chords — this is what I mean by “saturation.” (There are probably more precise ways of expressing this idea, but I don’t wish to get too technical, and in any case I’m no expert in 12-tone theory). This practice is predominant in much of Webern’s mature style, but I’m thinking especially of the Concerto Op. 24, whose tone row has so many symmetries, it is the musical equivalent of a magic square. Click this link to the Wikipedia article if you want a brief overview of the Concerto. Here I cannot help but use mathematical terminology: because the harmonic ‘domain’ is so restricted, eventually we begin to feel that the harmony is static, since we have practically exhausted all the permutations of the particular elements in the set. Note that I’m not trying to be obscure — ‘chord’ in 20th century music theory can be virtually any group of notes, and in more abstract contexts is usually called a pitch-class set. This tendency towards saturation might be one of the reasons why Webern’s compositions are so short, yet each is exquisitely crafted according to a rigorous logic.

Of course, the most important dimension is missing in this discussion: the human performer. While it is fascinating to discuss Webern’s music in abstract and theoretical terms, it is altogether a different experience to listen to it, or indeed to perform it. But that’s probably a discussion for another time.