Corollary 1
Tag 098Z, permanent. Cite it as [Bourbaki, Tag 098Z].
Integration, chapter VI, § 1. Integration of vector-valued functions
Let () be Hausdorff locally convex spaces having the property (GDF), and let be the space of separately continuous multilinear forms on , equipped with the topology of pointwise convergence. For every mapping of into that is scalarly essentially -integrable, one has .
The space is in duality with the tensor product , and the topology of pointwise convergence on is none other than the topology . The algebraic dual is therefore the space of all multilinear forms on . Let be an element of ; for every multilinear form , the mapping is a linear form on , which we shall denote by ; we thus obtain a linear mapping of into the algebraic dual of , continuous for the topologies and . To say that means that for every index and every , one has . Now, by Prop. 1 of No. 1, the mapping of is a scalarly essentially -integrable mapping of into equipped with the topology , and
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.