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arXiv · 0912.0822

Abstract Projective Lines

Anders Kock
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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.

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Anders Kock. 2009-12-04. Abstract Projective Lines. https://arxiv.org/abs/0912.0822

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