Theorem: ProbabilityTheory.Kernel.setIntegral_densityProcess
File: Mathlib/Probability/Kernel/Disintegration/Density.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
hA : MeasurableSet A
⊢ ∫ (x : γ) in A, κ.densityProcess ν n a x s ∂ν a = ((κ a) (A ×ˢ s)).toReal
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
hA : MeasurableSet A
this : IsFiniteKernel κ
⊢ ∫ (x : γ) in A, κ.densityProcess ν n a x s ∂ν a = ((κ a) (A ×ˢ s)).toReal
tactic: have : IsFiniteKernel κ := isFiniteKernel_of_isFiniteKernel_fst (h := isFiniteKernel_of_le hκν)
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
hA : MeasurableSet A
this : IsFiniteKernel κ
⊢ ∫ (x : γ) in A, κ.densityProcess ν n a x s ∂ν a = ((κ a) (A ×ˢ s)).toReal
state_after: case intro.intro
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
⊢ ∫ (x : γ) in ⋃₀ ↑S, κ.densityProcess ν n a x s ∂ν a = ((κ a) (⋃₀ ↑S ×ˢ s)).toReal
tactic: obtain ⟨S, hS_subset, rfl⟩ := (measurableSet_generateFrom_countablePartition_iff _ _).mp hA
state_before: case intro.intro
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
⊢ ∫ (x : γ) in ⋃₀ ↑S, κ.densityProcess ν n a x s ∂ν a = ((κ a) (⋃₀ ↑S ×ˢ s)).toReal
state_after: case intro.intro
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
⊢ ∫ (x : γ) in ⋃ i, ↑i, κ.densityProcess ν n a x s ∂ν a = ((κ a) ((⋃ i, ↑i) ×ˢ s)).toReal
tactic: simp_rw [sUnion_eq_iUnion]
state_before: case intro.intro
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
⊢ ∫ (x : γ) in ⋃ i, ↑i, κ.densityProcess ν n a x s ∂ν a = ((κ a) ((⋃ i, ↑i) ×ˢ s)).toReal
state_after: case intro.intro
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ ∫ (x : γ) in ⋃ i, ↑i, κ.densityProcess ν n a x s ∂ν a = ((κ a) ((⋃ i, ↑i) ×ˢ s)).toReal
tactic: have h_disj : Pairwise (Disjoint on fun i : S ↦ (i : Set γ)) := by
    intro u v huv
    #adaptation_note /-- nightly-2024-03-16
    Previously `Function.onFun` unfolded in the following `simp only`,
    but now needs a `rw`.
    This may be a bug: a no import minimization may be required.
    simp only [Finset.coe_sort_coe, Function.onFun] -/
    rw [Function.onFun]
    refine disjoint_countablePartition (hS_subset (by simp)) (hS_subset (by simp)) ?_
    rwa [ne_eq, ← Subtype.ext_iff]
state_before: case intro.intro
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ ∫ (x : γ) in ⋃ i, ↑i, κ.densityProcess ν n a x s ∂ν a = ((κ a) ((⋃ i, ↑i) ×ˢ s)).toReal
state_after: case intro.intro
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ ∑' (n_1 : ↑↑S), ∫ (x : γ) in ↑n_1, κ.densityProcess ν n a x s ∂ν a = ∑' (a_1 : ↑↑S), ((κ a) (↑a_1 ×ˢ s)).toReal

case intro.intro.hn
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ Pairwise (Disjoint on fun i => ↑i ×ˢ s)

case intro.intro.h
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ ∀ (i : ↑↑S), MeasurableSet (↑i ×ˢ s)

case intro.intro.hm
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ ∀ (i : ↑↑S), MeasurableSet ↑i

case intro.intro.hd
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ Pairwise (Disjoint on Subtype.val)

case intro.intro.hfi
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ : Kernel α (γ × β)
ν : Kernel α γ
hκν : κ.fst ≤ ν
inst✝ : IsFiniteKernel ν
n : ℕ
a : α
s : Set β
hs : MeasurableSet s
this : IsFiniteKernel κ
S : Finset (Set γ)
hS_subset : ↑S ⊆ countablePartition γ n
hA : MeasurableSet (⋃₀ ↑S)
h_disj : Pairwise (Disjoint on fun i => ↑i)
⊢ IntegrableOn (fun x => κ.densityProcess ν n a x s) (⋃ i, ↑i) (ν a)
tactic: rw [integral_iUnion, iUnion_prod_const, measure_iUnion,
      ENNReal.tsum_toReal_eq (fun _ ↦ measure_ne_top _ _)]