Definition 1

Tag 0183, permanent. Cite it as [Bourbaki, Tag 0183].

Lie Groups and Lie Algebras, chapter VIII, § 12. Chevalley orders

A lattice $\mathscr{H}$ in $\mathfrak{h}$ is said to be permissible (relative to $\mathfrak{g}$ ) if, for all $\alpha \in R$ , we have $H_{\alpha}\in \mathscr{H}$ and $\alpha (\mathscr{H})\subset \mathbf{Z}$ .

Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.

Cited by

Example 3, § 4
§ 12. Chevalley orders
§ 13. Classical splittable simple Lie algebras

Cites

Nothing.