Let us now pursue an apparently tangential path. We wish to consider one of the most fascinating and glamorous functions of analysis, the Riemann zeta function.
—Richard Bellman, A Brief Introduction to Theta Functions (1961)
Following Bellman’s lead, I’m going to take a break from falling objects with this discussion (don’t worry, we’ll get right back to that topic in the next discussion). This will be a mostly mathematical break, but at the end I will make a (speculative) connection with physics. So, consider the almost surely “too simple-looking to be important” double integral