Module: Mathlib.Probability.Independence.Kernel.Indep

Goal state before:
pp: α : Type u_1
Ω : Type u_2
_mα : MeasurableSpace α
m₂ m : MeasurableSpace Ω
κ : Kernel α Ω
μ : Measure α
inst✝ : IsZeroOrMarkovKernel κ
p1 p2 : Set (Set Ω)
h2 : m₂ ≤ m
hp2 : IsPiSystem p2
hpm2 : m₂ = generateFrom p2
hyp : IndepSets p1 p2 κ μ
t1 t2 : Set Ω
ht1 : t1 ∈ p1
ht1m : MeasurableSet t1
h : IsMarkovKernel κ
f : ℕ → Set Ω
hfd : Pairwise (Function.onFun Disjoint f)
hfm : ∀ (i : ℕ), MeasurableSet (f i)
ihf : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
a : α
ha : ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
⊢ ∑' (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (⋃ i, f i)

pp: case hn
α : Type u_1
Ω : Type u_2
_mα : MeasurableSpace α
m₂ m : MeasurableSpace Ω
κ : Kernel α Ω
μ : Measure α
inst✝ : IsZeroOrMarkovKernel κ
p1 p2 : Set (Set Ω)
h2 : m₂ ≤ m
hp2 : IsPiSystem p2
hpm2 : m₂ = generateFrom p2
hyp : IndepSets p1 p2 κ μ
t1 t2 : Set Ω
ht1 : t1 ∈ p1
ht1m : MeasurableSet t1
h : IsMarkovKernel κ
f : ℕ → Set Ω
hfd : Pairwise (Function.onFun Disjoint f)
hfm : ∀ (i : ℕ), MeasurableSet (f i)
ihf : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
a : α
ha : ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
⊢ Pairwise (Function.onFun Disjoint fun i ↦ t1 ∩ f i)

pp: case h
α : Type u_1
Ω : Type u_2
_mα : MeasurableSpace α
m₂ m : MeasurableSpace Ω
κ : Kernel α Ω
μ : Measure α
inst✝ : IsZeroOrMarkovKernel κ
p1 p2 : Set (Set Ω)
h2 : m₂ ≤ m
hp2 : IsPiSystem p2
hpm2 : m₂ = generateFrom p2
hyp : IndepSets p1 p2 κ μ
t1 t2 : Set Ω
ht1 : t1 ∈ p1
ht1m : MeasurableSet t1
h : IsMarkovKernel κ
f : ℕ → Set Ω
hfd : Pairwise (Function.onFun Disjoint f)
hfm : ∀ (i : ℕ), MeasurableSet (f i)
ihf : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
a : α
ha : ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
⊢ ∀ (i : ℕ), MeasurableSet (t1 ∩ f i)

Tactic:
measure_iUnion hfd fun i ↦ h2 _ (hfm i)

Goal state after:
α : Type u_1
Ω : Type u_2
_mα : MeasurableSpace α
m₂ m : MeasurableSpace Ω
κ : Kernel α Ω
μ : Measure α
inst✝ : IsZeroOrMarkovKernel κ
p1 p2 : Set (Set Ω)
h2 : m₂ ≤ m
hp2 : IsPiSystem p2
hpm2 : m₂ = generateFrom p2
hyp : IndepSets p1 p2 κ μ
t1 t2 : Set Ω
ht1 : t1 ∈ p1
ht1m : MeasurableSet t1
h : IsMarkovKernel κ
f : ℕ → Set Ω
hfd : Pairwise (Function.onFun Disjoint f)
hfm : ∀ (i : ℕ), MeasurableSet (f i)
ihf : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
a : α
ha : ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
⊢ ∑' (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * ∑' (i : ℕ), (κ a) (f i)

case hn
α : Type u_1
Ω : Type u_2
_mα : MeasurableSpace α
m₂ m : MeasurableSpace Ω
κ : Kernel α Ω
μ : Measure α
inst✝ : IsZeroOrMarkovKernel κ
p1 p2 : Set (Set Ω)
h2 : m₂ ≤ m
hp2 : IsPiSystem p2
hpm2 : m₂ = generateFrom p2
hyp : IndepSets p1 p2 κ μ
t1 t2 : Set Ω
ht1 : t1 ∈ p1
ht1m : MeasurableSet t1
h : IsMarkovKernel κ
f : ℕ → Set Ω
hfd : Pairwise (Function.onFun Disjoint f)
hfm : ∀ (i : ℕ), MeasurableSet (f i)
ihf : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
a : α
ha : ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
⊢ Pairwise (Function.onFun Disjoint fun i ↦ t1 ∩ f i)

case h
α : Type u_1
Ω : Type u_2
_mα : MeasurableSpace α
m₂ m : MeasurableSpace Ω
κ : Kernel α Ω
μ : Measure α
inst✝ : IsZeroOrMarkovKernel κ
p1 p2 : Set (Set Ω)
h2 : m₂ ≤ m
hp2 : IsPiSystem p2
hpm2 : m₂ = generateFrom p2
hyp : IndepSets p1 p2 κ μ
t1 t2 : Set Ω
ht1 : t1 ∈ p1
ht1m : MeasurableSet t1
h : IsMarkovKernel κ
f : ℕ → Set Ω
hfd : Pairwise (Function.onFun Disjoint f)
hfm : ∀ (i : ℕ), MeasurableSet (f i)
ihf : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
a : α
ha : ∀ (i : ℕ), (κ a) (t1 ∩ f i) = (κ a) t1 * (κ a) (f i)
⊢ ∀ (i : ℕ), MeasurableSet (t1 ∩ f i)