Bourbaki

Proposition 7

Tag 0A95, permanent. Cite it as [Bourbaki, Tag 0A95].

Lie Groups and Lie Algebras, chapter III, § 2. Group of tangent vectors to a Lie group

Let GG be a Lie group, MM a manifold of class CrC^r and ff and gg mappings of class CrC^r of MM into GG, so that fgfg is a mapping of class CrC^r of MM into GG. Let m∈M,x=f(m),y=g(m),u∈Tm(M)m \in M, x = f(m), y = g(m), u \in T_m(M). Then

(Tfg)u=T(f)u.y+x.T(g)u. (T fg)u = T(f)u.y + x.T(g)u.

Let mm be the multiplication of GG. Then fg=m∘(f,g)fg = m \circ (f, g). Now

T(f,g)(u)=(T(f)u,T(g)u), T(f, g)(u) = (T(f)u, T(g)u),

hence T(fg)u=T(f)u.T(g)uT(fg)u = T(f)u.T(g)u. It then suffices to apply (1) with ff replaced by mm.

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.