Bourbaki

Corollary 4

Tag 01EE, permanent. Cite it as [Bourbaki, Tag 01EE].

Lie Groups and Lie Algebras, chapter IX, § 5. Conjugacy classes

Every nilpotent subgroup of a compact Lie group is contained in the normalizer of a maximal torus.

Let H be a compact Lie group, N a nilpotent subgroup of H. Then the closure Γ\Gamma of N is also a nilpotent group (Chap. III, §9, no. 1, Cor. 2 of Prop. 1), and it suffices, in view of Cor. 3, to prove that Γ\Gamma satisfies condition (*). Now Γ0\Gamma_0 is a connected compact nilpotent Lie group, hence is a torus (§1, no. 4, Cor. 1 of Prop. 4), and there exists an element u1u_1 of Γ\Gamma generating a dense subgroup of Γ0(\Gamma_0(General Topology, Chap. VII, §1, no. 3, text preceding Prop. 8). The finite group Γ/Γ0\Gamma /\Gamma_0 is nilpotent and there exist u~2,...,u~n∈Γ/Γ0\widetilde{u}_2, . . . ,\widetilde{u}_n\in \Gamma /\Gamma_0 generating Γ/Γ0\Gamma /\Gamma_0 and such that the subgroup of Γ/Γ0\Gamma /\Gamma_0 generated by (u~2,...,u~r)(\widetilde{u}_2, . . . ,\widetilde{u}_r) is normal for r=2,...,n(r= 2, . . . , n(Algebra, Chap. I, §6, no. 5, Th. 1 and no. 7, Th. 4). Then, if u2,...,unu_2, . . . , u_n are representatives of u~2,...,u~n\widetilde{u}_2, . . . ,\widetilde{u}_n in Γ\Gamma, the sequence (u1,...,un)(u_1, . . . , u_n) has the required properties.

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

Nothing.

Cites

Transcribed from the printed volume. Not translated.