Bourbaki

Proposition 17

Tag 08M6, permanent. Cite it as [Bourbaki, Tag 08M6].

Integration, chapter III, § 1. Measures on a locally compact space

On the space M(X;C)\mathscr{M}(X; \mathbf{C}), consider the following topologies: T1\mathscr{T}_1: the topology of pointwise convergence in a total subset T of K(X;C)\mathscr{K}(X; \mathbf{C}); T2\mathscr{T}_2: the vague topology; T3\mathscr{T}_3: the topology of strictly compact convergence; T4\mathscr{T}_4: the topology of compact convergence. Each of these topologies is coarser than the next. Moreover: (i) The bounded sets are the same for T2\mathscr{T}_2, T3\mathscr{T}_3 and T4\mathscr{T}_4. (ii) If H is a vaguely bounded subset of M(X;C)\mathscr{M}(X; \mathbf{C}), the topologies induced on H by the topologies T1\mathscr{T}_1, T2\mathscr{T}_2, T3\mathscr{T}_3, T4\mathscr{T}_4 are identical.

A vaguely bounded subset HH of M(X;C)\mathscr{M}(X; \mathbf{C}) is equicontinuous (No. 9, Prop. 15), thus the first assertion follows from TVS, III, §3, No. 7, Prop. 9, and the second from GT, X, §2, No. 4, Th. 1.

Recall that when XX is paracompact, the topology of strictly compact convergence coincides with the topology of compact convergence (No. 1, Prop. 2).

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.