Obviously I'm not keeping up the blog too well; the notes are more reliably up-to-date.
Anyway:
Derived functors. Injective resolutions. Acyclic objects for a functor.
Theorem: a resolution by acyclic objects is good enough for computing derived functors.
The category of sheaves has enough injectives. Flasque sheaves. Injective sheaves are flasque, flasque are acyclic.
