Given composable left-exact functors F: A → B, G: B → C with F carrying injectives of A to G-acyclics, there is a spectral sequence R^p G ∘ R^q F ⇒ R^{p+q}(G∘F). Encodes how derived functors compose.
Given composable left-exact functors F: A → B, G: B → C with F carrying injectives of A to G-acyclics, there is a spectral sequence R^p G ∘ R^q F ⇒ R^{p+q}(G∘F). Encodes how derived functors compose.