∀ {α : Type u_1} {Ω : Type u_2} {ι : Type u_3} {_mα : MeasurableSpace α} {m : ι → MeasurableSpace Ω}
  {_mΩ : MeasurableSpace Ω} {κ : ProbabilityTheory.Kernel α Ω} {μ : MeasureTheory.Measure α} {s : ι → Set Ω}
  {S : Finset ι},
  ProbabilityTheory.Kernel.iIndep m κ μ →
    (∀ i ∈ S, MeasurableSet (s i)) → ∀ᵐ (a : α) ∂μ, (κ a) (⋂ i ∈ S, s i) = ∏ i ∈ S, (κ a) (s i)