Schemes 2: Etale spaces
Channel: Richard E Borcherds
Date: 2020-07-04

This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne.
In it we explain why the  obvious definition of an epimorphism of sheaves is wrong, and construct the etale space of a presheaf as preparation for giving the correct definition.