Skip to main content
8 events
when toggle format what by license comment
Oct 25, 2022 at 14:38 comment added Claudio Gorodski I think $\mathfrak g= \mathbb C^2 \rtimes \mathfrak{sl}_2\mathbb C$ is a counter example. The only real form is $\mathfrak g_0=\mathbb R^2 \rtimes \mathfrak{sl}_2\mathbb R$.
Oct 25, 2022 at 14:35 comment added Claudio Gorodski I asked if there exists $\mathfrak g_0$ such that $\mathfrak s_0$ is a compact Lie algebra. But now I think the result is false.
Oct 25, 2022 at 10:05 comment added Venkataramana I am not sure I understand. Levi Malcev theorem implies that the real form ${\mathfrak g}_0$ has a Levi decomposition whose complexification gives a Levi decomposition of $\mathfrak g$ and by the uniqueness of the Levi decomposition, must be the original Levi decomposition up to automorphism.
Oct 24, 2022 at 20:44 comment added Claudio Gorodski Yes, that is what I meant.
Oct 24, 2022 at 20:43 comment added Qiaochu Yuan To be clear, you mean "does there exist a real form of $\mathfrak{g}$ such that..."?
Oct 24, 2022 at 20:41 comment added Claudio Gorodski Thanks Qiaochu Yuan, I have edited the question.
Oct 24, 2022 at 20:40 history edited Claudio Gorodski CC BY-SA 4.0
Edited for clarity.
Oct 24, 2022 at 19:51 history asked Claudio Gorodski CC BY-SA 4.0