This is one of those things where I think there are 2 or 3 layers of math concepts above the concept of isogeny that I have to understand before I can understan

This is one of those things where I think there are 2 or 3 layers of math concepts above the concept of isogeny that I have to understand before I can understand isogenies. I tried following a trail upwards from isogeny and most of the related terms I didn't understand either. Nice.