Timeline for When representations of a Borel subgroup can be extended to a parabolic subgroup
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jan 30, 2014 at 17:52 | comment | added | Vít Tuček | I agree with Tom De Medts. I'm certainly no expert and my first guess would be $\langle \lambda, \alpha^\vee \rangle \in\mathbb{N}$. | |
| Jan 30, 2014 at 17:45 | comment | added | Tom De Medts | I don't agree that this question would not be research-level. This depends a lot on the background of the OP, and it is not unlikely that he came across this problem during his research in a different context but he does not have the required familiarity with algebraic groups, which is why he asked it on MO. This is a very good reason to use MO, in my humble opinion. | |
| Jan 30, 2014 at 14:43 | comment | added | Jim Humphreys | P.S. Strictly speaking, your semidirect product might be an "almost" semidirect product if the Levi subgroup has derived group $SL_2$ rather than $PGL_2$. But that has little effect on the situation. | |
| Jan 30, 2014 at 14:35 | comment | added | Jim Humphreys | I agree that the quetion is not research-level. It's worth comparing the deeper questions about extensions of representations in papers by Cline-Parshall-Scott Induced modules and extensions of representations, Invent. Math. 47 (1978), no. 1, 41–51, Induced modules and extensions of representations II, J. London Math. Soc. (2) 20 (1979), no. 3, 403–414, and by H.H. Andersen Vanishing theorems and induced representations, J. Algebra 62 (1980), no. 1, 86–100. | |
| Jan 30, 2014 at 10:21 | history | answered | Allen Knutson | CC BY-SA 3.0 |