Bourbaki

Proposition 19

Tag 0A9X, permanent. Cite it as [Bourbaki, Tag 0A9X].

Lie Groups and Lie Algebras, chapter III, § 3. Passage from a Lie group to its Lie algebra

Let t∈T(s)(G)t \in \mathscr{T}^{(s)}(G), with s≤rs \leq r. Let ff (resp. f′f') be a function of class CrC^r on XX with values in a Hausdorff polynormed space FF (resp. F′F'). Let (u,u′)↦uu′(u, u') \mapsto uu' be a continuous bilinear mapping of F×F′F \times F' into a Hausdorff polynormed space F′′F'', so that ff′ff' is a function of class CrC^r on XX with values in F′′F''. Let

∑i=1nti⊗ti′ be the image of t in T(s)(G)⊗T(s)(G) under the coproduct. Then \sum_{i=1}^n t_i \otimes t'_i \text{ be the image of } t \text{ in } \mathscr{T}^{(s)}(G) \otimes \mathscr{T}^{(s)}(G) \text{ under the coproduct. Then}
t∗(ff′)=∑i=1n(ti∗f)(ti′∗f′). t * (ff') = \sum_{i=1}^n (t_i * f)(t'_i * f').

Let x∈Xx \in X and let ρ(x)\rho(x) denote the orbital mapping of xx. Then

⟨εx,t∗(ff′)⟩=⟨t∨,(ff′)∘ρ(x)⟩by (4)=⟨t∨,(f∘ρ(x))(f′∘ρ(x))⟩=∑i=1n⟨ti∨,f∘ρ(x)⟩⟨ti′∨,f′∘ρ(x)⟩=∑i=1n⟨εx,ti∗f⟩⟨εx,ti′∗f′⟩by (4).(Diff. & Man. Anal., R, 13.5.2) \langle \varepsilon_x, t * (ff') \rangle = \langle t^\vee, (ff') \circ \rho(x) \rangle \quad \text{by (4)} \\ = \langle t^\vee, (f \circ \rho(x))(f' \circ \rho(x)) \rangle \\ = \sum_{i=1}^n \langle t_i^\vee, f \circ \rho(x) \rangle \langle t_{i'}^\vee, f' \circ \rho(x) \rangle \tag{Diff. \& Man. Anal., R, 13.5.2} \\ = \sum_{i=1}^n \langle \varepsilon_x, t_i * f \rangle \langle \varepsilon_x, t_i' * f' \rangle \quad \text{by (4).}

Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.

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Cites

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Transcribed from the printed volume. Not translated.