Let's start with something simple: Given a circle with radius $R$, draw a concentric circle with radius 1 larger. How much longer is …

When does a polynomial with real coefficients have only real roots? Here's one way to determine it.

Driving down the highway in upstate Michigan yesterday, I saw a State Police billboard that states (I paraphrase)
Drivers who text are …

Here's a slightly non-obvious relation between some angles, that I ran into accidentally.
Claim: (angles below given in degrees)
\[ …

A short note about an implicit assumption behind the notion of expectation values, and how it relates to economics applications.

I try to reformulate an idea of Capoferri and Vassiliev in the infinitesimal limit and see where it goes.

Some introductory notes about the definition and geometry of Lie groups, and their analysis.

As we all learned in a first course in PDEs, for "reasonable" initial data $u_0$, the solution to the linear heat equation …

This post is about the formulation of the dynamics of a rigid body, under rotations, as dynamics on a Lie group. I'm writing this to …