Schemes 11: Gluing schemes
This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne.
We give two examples of gluing affine schemes to get non-affine schemes:
the line with two origins and the projective line. We calculate the regular functions on these schemes, and investigate the points of the projective line over a ring, which turn out to be more complicated than one might expect.