Paper 5: NTLA-O IV: Local–Global Observation, Presheaves, Sheaves, Stalks, and Descent

Local-to-Global Observation — Presheaves, Sheaves, Stalks, Germs, and Descent

NTLA-O series Paper 5. Represents the internal observer as a local section over open sets of the observer topology, defining, for each open set, an admissible local observational-state set and restriction map. Studies when data from different local observers can compatibly glue into a global state (the sheaf condition), and the global reconstruction obstruction when gluing fails (descent obstruction).