Timeline for "Forms" of quadrics
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 13, 2017 at 12:58 | history | edited | CommunityBot |
replaced http://mathoverflow.net/ with https://mathoverflow.net/
|
|
| Sep 23, 2014 at 15:36 | comment | added | Daniel Loughran | In fact it is not too difficult to compute, at least over number fields (note that it is a pointed set, not a group). This is more or less the classification of quadratic forms in terms of the discriminant, Hasse-Witt invariant and signature, plus taking care of the cokernel of the above map I give, which should not be too difficult. These are all cohomological invariants which arise from considering various exact sequence of groups related to $\mbox{O},\mbox{SO}, \mbox{PO}$ and $\mbox{Spin}$. | |
| Sep 23, 2014 at 15:29 | comment | added | Wanderer | I realized that $H^1(k,\mathrm{PO}(Q))$ would classify these twists, but I didn't want to try computing this group -- it might be painful? :-) Very nice example! | |
| Sep 23, 2014 at 15:22 | vote | accept | Wanderer | ||
| Sep 23, 2014 at 15:19 | history | edited | Daniel Loughran | CC BY-SA 3.0 |
added 548 characters in body
|
| Sep 23, 2014 at 15:14 | history | edited | Daniel Loughran | CC BY-SA 3.0 |
added 548 characters in body
|
| Sep 23, 2014 at 15:09 | history | answered | Daniel Loughran | CC BY-SA 3.0 |