Timeline for Kontsevich space in positive characteristic
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 17, 2017 at 2:37 | vote | accept | DCT | ||
| Nov 15, 2017 at 17:44 | answer | added | Jason Starr | timeline score: 10 | |
| Nov 15, 2017 at 16:49 | comment | added | Jason Starr | * "find" --> "fine" | |
| Nov 15, 2017 at 16:42 | comment | added | Jason Starr | However, depending on what aspect of the stacks you are studying, it may be that the nonreduced automorphism groups are find, causing no problems. However, this does cause a problem with the description of the cotangent complex of the stack. The cotangent complex is one of the ingredients in the construction of virtual fundamental classes by Behrend and Fantechi. For that purpose, you could always construct the cycle class in characteristic $0$ and try to use the specialization map to extend the cycle class to positive characteristic. | |
| Nov 15, 2017 at 16:38 | comment | added | Jason Starr | They are not Deligne-Mumford stacks, because the map may be inseparable. So automorphism group schemes of maps may include nonreduced groups such as $\mu_p$ (the automorphism group scheme of the map $z\mapsto z^p$ on $\mathbb{P}^1)$ or $\alpha_p$ (the automorphism group scheme of certain isogenies of elliptic curves). | |
| Nov 15, 2017 at 16:32 | history | asked | DCT | CC BY-SA 3.0 |