Module: Mathlib.Probability.Kernel.Disintegration.Density

Goal state before:
pp: case iUnion
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
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
this : IsFiniteKernel κ
hgen : mγ = generateFrom {s | ∃ n, MeasurableSet s}
hpi : IsPiSystem {s | ∃ n, MeasurableSet s}
f : ℕ → Set γ
hf_disj : Pairwise (Function.onFun Disjoint f)
hf : ∀ (i : ℕ), MeasurableSet (f i)
h_eq : ∀ (i : ℕ), ∫ (x : γ) in f i, κ.density ν a x s ∂ν a = (κ a).real (f i ×ˢ s)
⊢ ∑' (a_1 : ℕ), (κ a) (f a_1 ×ˢ s) = ∑' (i : ℕ), (κ a) (f i ×ˢ s)

pp: case iUnion.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
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
this : IsFiniteKernel κ
hgen : mγ = generateFrom {s | ∃ n, MeasurableSet s}
hpi : IsPiSystem {s | ∃ n, MeasurableSet s}
f : ℕ → Set γ
hf_disj : Pairwise (Function.onFun Disjoint f)
hf : ∀ (i : ℕ), MeasurableSet (f i)
h_eq : ∀ (i : ℕ), ∫ (x : γ) in f i, κ.density ν a x s ∂ν a = (κ a).real (f i ×ˢ s)
⊢ Pairwise (Function.onFun Disjoint fun i ↦ f i ×ˢ s)

pp: case iUnion.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
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
this : IsFiniteKernel κ
hgen : mγ = generateFrom {s | ∃ n, MeasurableSet s}
hpi : IsPiSystem {s | ∃ n, MeasurableSet s}
f : ℕ → Set γ
hf_disj : Pairwise (Function.onFun Disjoint f)
hf : ∀ (i : ℕ), MeasurableSet (f i)
h_eq : ∀ (i : ℕ), ∫ (x : γ) in f i, κ.density ν a x s ∂ν a = (κ a).real (f i ×ˢ s)
⊢ ∀ (i : ℕ), MeasurableSet (f i ×ˢ s)

Tactic:
]

Goal state after:
case iUnion.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
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
this : IsFiniteKernel κ
hgen : mγ = generateFrom {s | ∃ n, MeasurableSet s}
hpi : IsPiSystem {s | ∃ n, MeasurableSet s}
f : ℕ → Set γ
hf_disj : Pairwise (Function.onFun Disjoint f)
hf : ∀ (i : ℕ), MeasurableSet (f i)
h_eq : ∀ (i : ℕ), ∫ (x : γ) in f i, κ.density ν a x s ∂ν a = (κ a).real (f i ×ˢ s)
⊢ Pairwise (Function.onFun Disjoint fun i ↦ f i ×ˢ s)

case iUnion.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
a : α
s : Set β
hs : MeasurableSet s
A : Set γ
this : IsFiniteKernel κ
hgen : mγ = generateFrom {s | ∃ n, MeasurableSet s}
hpi : IsPiSystem {s | ∃ n, MeasurableSet s}
f : ℕ → Set γ
hf_disj : Pairwise (Function.onFun Disjoint f)
hf : ∀ (i : ℕ), MeasurableSet (f i)
h_eq : ∀ (i : ℕ), ∫ (x : γ) in f i, κ.density ν a x s ∂ν a = (κ a).real (f i ×ˢ s)
⊢ ∀ (i : ℕ), MeasurableSet (f i ×ˢ s)