Section 3.3 Exact Functors - Categories & Sheaves

We introduce Kashiwara and Schapira's (cursed) version of exactness, and then explain what's going on with it by doing one example in gory detail. We prove the equivalence of exactness in this sense with the familiar property of commuting with co/limits.

Actually, I only prove one direction, because I just straight up forgot. Thankfully, the other direction is very easy. It's actually just a consequence of a bunch of results we already have. Namely, if a functor commutes with e.g. finite projective limits, then C^U, which has finite projective limits, is cofiltrant, which is our definition of e.g. left exactness. You can fill in the rest if you're not sure.

(and please talk in it! It's gotten very quiet because I'm slow at making content as a grad student.)