Bourbaki

Corollary

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

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

For all g∈Gg \in G,

δ(g)∗ω=(det⁡Ad g)ω. \delta(g)^*\omega = (\det \mathrm{Ad}\, g) \omega.
δ(g)∗ω=δ(g)∗γ(g)∗ω=(Int g)∗ω and L(Int g)=Ad g. \delta(g)^*\omega = \delta(g)^*\gamma(g)^*\omega = (\mathrm{Int}\, g)^*\omega \text{ and } L(\mathrm{Int}\, g) = \mathrm{Ad}\, g.

Let G be a locally compact group and φ an endomorphism of G. Suppose that there exist open neighbourhoods V, V′V' of e such that ϕ(V)=V′\phi(V) = V' and ϕ∣V\phi|V is a local isomorphism of G into G. Let μ be a left Haar measure on G. By Integration, Chapter VII, § 1, Corollary to Proposition 9, there exists a unique number a>0a > 0 such that ϕ(μ∣V)=a−1μ∣V′\phi(\mu|V) = a^{-1}\mu|V'. Clearly a is independent of the choice of V, V′V' and μ. It is called the modulus of φ and is denoted by modGϕ\mathrm{mod}_G \phi or simply mod ϕ\mathrm{mod}\, \phi. When φ is an automorphism of G, we recover Definition 4 of Integration, Chapter VII, § 1.

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

Cited by

Cites

  • Definition 4 of Integration, Chapter VII, § 1 not yet on this site: INT VII
  • Integration, Chapter VII, § 1, Corollary to Proposition 9 not yet on this site: INT VII
Transcribed from the printed volume. Not translated.