An Evans Function: A Wronskian on Crack

Definition: An Evans function is a Wronskian on crack.

I'm pretty sure that this is the official definition that you'll find in many mathematics books.

In case you're interested in these objects, see Todd Kapitula's primer. And here is a new article by Chris Jones that reminded me of the above definition.

Actually, I'm pretty sure I once heard someone — maybe even Chris? — joking call an Evans function "a Wronskian on steroids" during a seminar. I remember thinking that 'on steroids' probably wasn't doing justice to the function.

Spectral Graph Theory: Cover Art

Here is my new cover art for the field of spectral graph theory. (I couldn't wait until Halloween to make this picture.)

A Spectral Navigation Algorithm

Clearly, some users of London's transportation system are using a spectral algorithm for navigation.

(Tip of the cap to Sang Hoon Lee.)

An Eigencheese Sandwich

This spectral graph theory workshop is clearly getting to me: a few minutes ago, "egg and cheese sandwich" sounded like "eigencheese sandwich" to me.