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.