Timeline for Are Lie groupoids just groupoids internal to smooth manifolds?
Current License: CC BY-SA 4.0
3 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 4 at 20:43 | comment | added | Konrad Waldorf | @AlonsoPerez-Lona: interesting! I am getting more and more convinced that there is no example... | |
| Apr 4 at 19:49 | comment | added | Alonso Perez-Lona | As you mentioned, the surjective submersion condition is imposed so that the fiber product exists as a smooth manifold, as in this case one has a transversal intersection. But this is only a sufficient condition for the pullback to exist, in principle one could require the source and target maps to only define a clean intersection (which is strictly weaker than transversal) and the fiber product would still exist. That being said, Mackenzie in his Lie groupoids book comments on this in p.85 saying he is not aware of an example where the source and target maps are not surjective submersions. | |
| Apr 2 at 8:15 | history | asked | Konrad Waldorf | CC BY-SA 4.0 |