Timeline for automorphism group and group presentation
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 11, 2013 at 2:47 | comment | added | Lee Mosher | I deleted my comment that the fundamental group of the Klein bottle is an example, I forgot that the Dehn twist makes the automorphism group infinite. | |
| Apr 11, 2013 at 2:39 | comment | added | Misha | Indeed, such group G would have to have finite automorphism group. Looking at the inner automorphisms, one immediately sees that G is either finite or is an extension of the infinite cyclic group with finite kernel: $1\to F \to G \to Z\to 1$, where F is finite. | |
| Apr 11, 2013 at 1:52 | comment | added | Misha | Very rarely, I think it has to be either finite or be virtually Z. | |
| Apr 11, 2013 at 1:33 | history | asked | Russell | CC BY-SA 3.0 |