Skip to the Main Content

Note:These pages make extensive use of the latest XHTML and CSS Standards. They ought to look great in any standards-compliant modern browser. Unfortunately, they will probably look horrible in older browsers, like Netscape 4.x and IE 4.x. Moreover, many posts use MathML, which is, currently only supported in Mozilla. My best suggestion (and you will thank me when surfing an ever-increasing number of sites on the web which have been crafted to use the new standards) is to upgrade to the latest version of your browser. If that's not possible, consider moving to the Standards-compliant and open-source Mozilla browser.

November 22, 2025

Beyond the Geometry of Music

Posted by John Baez

Yesterday I had a great conversation with Dmitri Tymoczko about groupoids in music theory. But at this Higgs Centre Colloquium, he preferred to downplay groupoids and talk in a way physicists would enjoy more. Click here to watch his talk!

What’s great is that Tymoczkyo not faking it: he’s really found deep ways in which symmetry shows up pervasively in music.

At first he tried to describe them geometrically using orbifolds, which are spaces in which some singular points have nontrivial symmetry groups, like the tip of a cone formed by modding out the plane by the action of the group /n\mathbb{Z}/n. But then he realized that the geometry was less important than the symmetry, which you can describe using groupoids. That’s why his talk is called “Beyond the geometry of music”.

I’m helping him with his work on groupoids, and I hope he explains his work to mathematicians someday without pulling his punches. I didn’t get to interview him yesterday, but I’ll try to do that soon.

For now you can read his books A Geometry of Music and Harmony: an Owner’s Manual along with many papers. What I’ve read so far is really exciting.

Posted at November 22, 2025 4:05 PM UTC

TrackBack URL for this Entry:   https://golem.ph.utexas.edu/cgi-bin/MT-3.0/dxy-tb.fcgi/3622

0 Comments & 0 Trackbacks

Post a New Comment