Prefer a chat interface with context about you and your work?
About <i>q</i>-approximations and <i>q</i>-hulls over a Noetherian ring, some refinements of the Auslander-Bridger theory
We revisit the notion of q-approximations for a module over a Noetherian ring, originally due to Auslander and Bridger without a name and rediscovered later by Evans and Griffith. We introduce a somewhat symmetric notion of q-hull and provide existence theorems for both q-approximations and q-hulls. The main feature here …