Bourbaki

Proposition 18

Tag 0A9W, permanent. Cite it as [Bourbaki, Tag 0A9W].

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), t′∈T(s′)(G)t' \in \mathscr{T}^{(s')}(G) and f:X→Ff : X \to F a function of class CrC^r, with s+s′≤rs + s' \leq r. Then

(t∗t′)∗f=t∗(t′∗f). (t * t') * f = t * (t' * f).
For all x∈Xx \in X,
⟨εx,(t∗t′)∗f⟩=⟨((t∗t′)∨∗εx),f⟩by (5)=⟨t′∨∗(t∨∗εx),f⟩(Propositions 2 and 7)=⟨t∨∗εx,t′∗f⟩(Proposition 17)=⟨εx,t∗(t′∗f)⟩(Proposition 17). \begin{align*} \langle \varepsilon_x, (t * t') * f \rangle &= \langle ((t * t')^\vee * \varepsilon_x), f \rangle \quad \text{by (5)} \\ &= \langle {t'}^\vee * (t^\vee * \varepsilon_x), f \rangle \quad (\text{Propositions 2 and 7}) \\ &= \langle t^\vee * \varepsilon_x, t' * f \rangle \quad (\text{Proposition 17}) \\ &= \langle \varepsilon_x, t * (t' * f) \rangle \quad (\text{Proposition 17}). \end{align*}

If r≥∞r \geq \infty, we see that the set of functions of class C∞C^\infty on XX with values in FF is a left module over the algebra T(∞)(G)\mathscr{T}^{(\infty)}(G).

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

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Transcribed from the printed volume. Not translated.