Image integrals from pulled-back densities
ProvedMeasurableEmbedding.exists_vectorMeasure_image_integralmeasure-theory
Pulling an integrable density back along a measurable embedding gives its image integrals via the comap withDensity measure.
Preamble
import Mathlib.MeasureTheory.VectorMeasure.WithDensity import Mathlib.MeasureTheory.Integral.Bochner.Set import Mathlib.MeasureTheory.Integral.IntegrableOn open Set MeasureTheory
Formal statement
namespace MeasurableEmbedding
theorem exists_vectorMeasure_image_integral
{α β E : Type*} [MeasurableSpace α] [MeasurableSpace β]
[NormedAddCommGroup E] [NormedSpace ℝ E]
{f : α → β} (hf : MeasurableEmbedding f) (μ : Measure β) (g : β → E)
(hg : Integrable g μ) :
∃ ν : VectorMeasure α E, ∀ s, MeasurableSet s → ν s = ∫ x in f '' s, g x ∂μ := by sorry
end MeasurableEmbeddingSource
MovingSofa/ForMathlib/MeasureTheory/VectorMeasure/Interval.lean (second theorem)