Timeline for Action of Coxeter element on mod $2$ root lattice is semisimple
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 23, 2021 at 10:15 | comment | added | Paul Levy | An element of even order never acts semisimply on a vector space in characteristic $2$. A Coxeter element has even order except in type $A_{2m}$. The only caveat is that sometimes the Weyl group has a kernel for its action on the roots, so it's the order of the Coxeter element in this quotient that matters. | |
| Oct 22, 2021 at 15:57 | vote | accept | Jef | ||
| Oct 22, 2021 at 11:20 | answer | added | Andrei Smolensky | timeline score: 2 | |
| Oct 22, 2021 at 9:57 | history | asked | Jef | CC BY-SA 4.0 |