[[!redirects Kock_5]] ###Reference Details### +-- cite key : Kock_5 title : Projective lines as groupoids with projection structure author : Kock, A. eprint : <http://arxiv.org/abs/1310.5357v1> mrclass : math.CT note : arXiv:1310.5357v1 url : <http://arxiv.org/abs/1310.5357v1> arxiv : [1310.5357](http://www.arxiv.org/abs/1310.5357) refbase : [2123](http://www.math.ntnu.no/~stacey/RefBase/show.php?record=2123) =-- {: .bibliography} --- category: category theory