Abstract Projective Lines
Algebraic Geometry
2009-12-07 v1
Abstract
We describe a notion of (abstract) projective line over a field as a set equipped with a certain first order structure, and a projectivity between projective lines as a bijection preserving this structure. The structure in question is that of a groupoid, with certain properties. This leads to a natural notion of bundle of projective lines, forming a stack.
Keywords
Cite
@article{arxiv.0912.0822,
title = {Abstract Projective Lines},
author = {Anders Kock},
journal= {arXiv preprint arXiv:0912.0822},
year = {2009}
}