Talk:Groupoid

"different geometry [a3]" — really? Maybe, differential geometry? Boris Tsirelson (talk) 19:59, 13 December 2015 (CET)

The phrase is in the original text. But chapter 5 of Kock, Anders, Synthetic geometry of manifolds, Cambridge Tracts in Mathematics 180, Cambridge University Press (2010) ISBN 978-0-521-11673-2 Zbl 1210.51001 suggests that you are quite right. Richard Pinch (talk) 20:15, 13 December 2015 (CET)