Corollary 2
Tag 0AEI, permanent. Cite it as [Bourbaki, Tag 0AEI].
Lie Groups and Lie Algebras, chapter III, § 6. Real and complex Lie groups
Let G be a Lie group and H1 and H_2 integral subgroups of G. If , then H_2 is an integral subgroup of H_1.*
Let be the canonical injections. Then
By Proposition 1, is an analytic mapping of into and even an immersion of into since is an isomorphism of onto a subalgebra of admitting a topological supplement.
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.