Product of vector measures #
Given two vector measures, we define their product μ.prod ν B as the vector measure assigning
to a measurable product s × t the mass B (μ s) (ν t), if such a vector measure exists.
We show that it exists when either μ or ν has finite variation.
When both measures have finite variation, we prove stronger results, notably versions of the Fubini theorem. We give general versions for arbitrary pairing functions, and specialized versions for scalar multiplication.
The API is modelled on the one for the product of positive measures.
Two vector measures μ and ν have a product with respect to B if there exists a
measure giving mass B (μ s) (ν t) to any measurable product set s × t.
This is satisfied whenever μ or ν has finite variation.
- exists_prod : ∃ (ρ : VectorMeasure (X × Y) G), ∀ (s : Set X) (t : Set Y), MeasurableSet s → MeasurableSet t → ρ (s ×ˢ t) = (B (μ s)) (ν t)
Instances
The product of two vector measures μ and ν with respect to a continuous bilinear map B,
giving mass B (μ s) (ν t) to any measurable product set s × t.
If such a measure does not exist, we use the junk value 0.
Instances For
If ν is a vector measure, and s ⊆ X × Y is measurable, then x ↦ ν { y | (x, y) ∈ s } is
a strongly measurable function.
The vector measure integral is measurable. This shows that the integrand of (the right-hand-side
of) Fubini's theorem is measurable. This version has f in curried form.
The vector measure integral is measurable. This shows that the integrand of (the right-hand-side of) Fubini's theorem is measurable.
The vector measure integral is measurable. This shows that the integrand of (the right-hand-side
of) the symmetric version of Fubini's theorem is measurable.
This version has f in curried form.
The vector measure integral is measurable. This shows that the integrand of (the right-hand-side of) the symmetric version of Fubini's theorem is measurable.
The vector measure integral is a.e.-measurable. This shows that the integrand of (the right-hand-side of) Fubini's theorem is a.e.-measurable.
Vector measure integrals commute with subtraction inside a lower Lebesgue integral.
The map that sends an L¹-function f : X × Y → G to ∫∫f is continuous.
Fubini's Theorem: For integrable functions on X × Y,
the vector measure integral of f for the product vector measure is equal to the iterated vector
measure integral. We express this with respect to general pairing functions, with a compatibility
condition saying that the compositions coincide up to reordering.
Fubini's Theorem: For integrable functions on X × Y,
the vector measure integral of f for the product vector measure is equal to the iterated vector
measure integral. Version where f is scalar.
Symmetric version of Fubini's Theorem: For integrable functions on X × Y,
the vector measure integral of f for the product vector measure is equal to the iterated vector
measure integral. We express this with respect to general pairing functions, with a compatibility
condition saying that the compositions coincide up to reordering.
This version has the integrals on the right-hand side in the other order.
Fubini's Theorem: For integrable functions on X × Y,
the vector measure integral of f for the product vector measure is equal to the iterated vector
measure integral. Version where f is scalar.
This version has the integrals on the right-hand side in the other order.
Reversed version of Fubini's Theorem.
Reversed version of Fubini's Theorem, version with a scalar function.
Reversed version of Fubini's Theorem (symmetric version).
Reversed version of Fubini's Theorem (symmetric version), version with a scalar function.
Change the order of integration in integrals wrt vector measures. We express this with respect to general pairing functions, with a compatibility condition saying that the compositions coincide up to reordering.
Change the order of integration in integrals wrt vector measures.
Case where f is scalar.