Expository

This is a collection some of the expository notes that I have written, they range in topic, some closer to my research and some farther away. As opposed to posts in "Mathematical Diversions", posts here are intended to be read by other people. I welcome comments and corrections.

We introduce the Kodama vector field for rotationally symmetric space-times and its relation to gravitational red-shift.
Last updated on 15 min read expository

I've just spent much too long puzzling over the geometric formalism of a paper of Lazar and Hehl, so I figure I'll write a little …
Last updated on 11 min read expository

We give a proof of the irrationality of π.
Last updated on 5 min read expository

We explain how to conformally compactify Lorentzian manifolds.
Last updated on 12 min read expository

Lecture notes on a fake derivation of the Kerr metric from the Schwarzschild metric, based on lots of hindsight.
Last updated on 1 min read expository