Theorem: ProbabilityTheory.eq_condKernel_of_measure_eq_compProd_real
File: Mathlib/Probability/Kernel/Disintegration/Unique.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
⊢ ∀ᵐ (x : α) ∂ρ.fst, κ x = ρ.condKernel x
state_after: α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst, κ x = ρ.condKernel x
tactic: have huniv : ∀ᵐ x ∂ρ.fst, κ x Set.univ = ρ.condKernel x Set.univ :=
    eq_condKernel_of_measure_eq_compProd' κ hκ MeasurableSet.univ
state_before: α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst, κ x = ρ.condKernel x
state_after: α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst, ∀ ⦃t : Set ℝ⦄, MeasurableSet t → (κ x) t = (ρ.condKernel x) t
tactic: suffices ∀ᵐ x ∂ρ.fst, ∀ ⦃t⦄, MeasurableSet t → κ x t = ρ.condKernel x t by
    filter_upwards [this] with x hx
    ext t ht; exact hx ht
state_before: α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst, ∀ ⦃t : Set ℝ⦄, MeasurableSet t → (κ x) t = (ρ.condKernel x) t
state_after: case h_empty
α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst, (κ x) ∅ = (ρ.condKernel x) ∅

case h_basic
α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst, ∀ t ∈ ⋃ a, {Iic ↑a}, (κ x) t = (ρ.condKernel x) t

case h_compl
α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst, ∀ (t : Set ℝ), MeasurableSet t → (κ x) t = (ρ.condKernel x) t → (κ x) tᶜ = (ρ.condKernel x) tᶜ

case h_union
α : Type u_1
β : Type u_2
Ω : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
inst✝⁵ : MeasurableSpace Ω
inst✝⁴ : StandardBorelSpace Ω
inst✝³ : Nonempty Ω
ρ✝ : Measure (α × Ω)
inst✝² : IsFiniteMeasure ρ✝
ρ : Measure (α × ℝ)
inst✝¹ : IsFiniteMeasure ρ
κ : Kernel α ℝ
inst✝ : IsFiniteKernel κ
hκ : ρ = ρ.fst ⊗ₘ κ
huniv : ∀ᵐ (x : α) ∂ρ.fst, (κ x) univ = (ρ.condKernel x) univ
⊢ ∀ᵐ (x : α) ∂ρ.fst,
    ∀ (f : ℕ → Set ℝ),
      Pairwise (Disjoint on f) →
        (∀ (i : ℕ), MeasurableSet (f i)) →
          (∀ (i : ℕ), (κ x) (f i) = (ρ.condKernel x) (f i)) → (κ x) (⋃ i, f i) = (ρ.condKernel x) (⋃ i, f i)
tactic: apply MeasurableSpace.ae_induction_on_inter Real.borel_eq_generateFrom_Iic_rat
    Real.isPiSystem_Iic_rat