Bourbaki

Definition 1

Tag 0910, permanent. Cite it as [Bourbaki, Tag 0910].

Integration, chapter V, § 3. Integration of positive measures

— *Let XX be a locally compact space, Λ:t↦λt\Lambda : t \mapsto \lambda_t a scalarly essentially μ\mu-integrable mapping of TT into M+(X)\mathscr{M}_+(X), and ν\nu the integral of Λ\Lambda.

We say that Λ\Lambda is μ\mu-pre-adequate if, for every lower semi-continuous function f≥0f \geq 0 defined on XX, the function t↦∫∙fdλtt \mapsto \int^\bullet f d\lambda_t is μ\mu-measurable on TT and*

∫∙f(x)dν(x)=∫∙dμ(t)∫∙f(x)dλt(x). \int^\bullet f(x) d\nu(x) = \int^\bullet d\mu(t) \int^\bullet f(x) d\lambda_t(x).

We say that Λ\Lambda is μ\mu-adequate () if Λ\Lambda is μ′\mu'-pre-adequate for every positive measure μ′≤μ\mu' \leq \mu.*

It can be shown that if Λ\Lambda is μ\mu-pre-adequate and if the measure ν=∫λtdμ(t)\nu = \int \lambda_t d\mu(t) is moderated—in particular if XX is countable at infinity—then Λ\Lambda is μ\mu-adequate (Exer. 7); however, it is not known if these concepts are in general equivalent. In the statements in Nos. 2 and 3 below, the assertions preceded by an a) or a b) extend at once to pre-adequate mappings, whereas those preceded by a c) are valid only for adequate mappings.

(*) In the first edition, ' μ\mu-adequate' mappings were defined to be the scalarly essentially μ\mu-integrable and vaguely μ\mu-measurable mappings. The definition given here is more general (Prop. 2 below).

The following proposition often permits one to verify that a given mapping is μ\mu-adequate.

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.