Theorem: ProbabilityTheory.kernel.iIndepSets.indepSets
File: Mathlib/Probability/Independence/Kernel.lean

tactic: intro t₁ t₂ ht₁ ht₂
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
⊢ IndepSets (s i) (s j) κ μ
state_after: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂

tactic: have h1 : t₁ = ite (i = i) t₁ t₂ := by simp only [if_true, eq_self_iff_true]
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂
state_after: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂

tactic: have h2 : t₂ = ite (j = i) t₁ t₂ := by simp only [hij.symm, if_false]
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂
state_after: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂

tactic: have h_inter : ⋂ (t : ι) (_ : t ∈ ({i, j} : Finset ι)), ite (t = i) t₁ t₂ =
    ite (i = i) t₁ t₂ ∩ ite (j = i) t₁ t₂ := by
  simp only [Finset.set_biInter_singleton, Finset.set_biInter_insert]
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂
state_after: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂

tactic: filter_upwards [h_indep {i, j} hf_m] with a h_indep'
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
⊢ ∀ᵐ (a : α) ∂μ, (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂
state_after: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
⊢ (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂

tactic: have h_prod : (∏ t ∈ ({i, j} : Finset ι), κ a (ite (t = i) t₁ t₂))
    = κ a (ite (i = i) t₁ t₂) * κ a (ite (j = i) t₁ t₂) := by
  simp only [hij, Finset.prod_singleton, Finset.prod_insert, not_false_iff,
    Finset.mem_singleton]
state_before: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
⊢ (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂
state_after: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂

tactic: rw [h1]
state_before: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) (t₁ ∩ t₂) = (κ a) t₁ * (κ a) t₂
state_after: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) ((if i = i then t₁ else t₂) ∩ t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) t₂

tactic: nth_rw 2 [h2]
state_before: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) ((if i = i then t₁ else t₂) ∩ t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) t₂
state_after: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) ((if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) t₂

tactic: nth_rw 4 [h2]
state_before: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) ((if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) t₂
state_after: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) ((if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂) =
    (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)

tactic: rw [← h_inter, ← h_prod, h_indep']
state_before: case h
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
h_prod :
  ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
⊢ (κ a) ((if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂) =
    (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
state_after: no goals

tactic: intro x hx
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
⊢ ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
state_after: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
x : ι
hx : x ∈ {i, j}
⊢ (if x = i then t₁ else t₂) ∈ s x

tactic: cases' Finset.mem_insert.mp hx with hx hx
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
x : ι
hx : x ∈ {i, j}
⊢ (if x = i then t₁ else t₂) ∈ s x
state_after: case inl
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
x : ι
hx✝ : x ∈ {i, j}
hx : x = i
⊢ (if x = i then t₁ else t₂) ∈ s x

case inr
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
x : ι
hx✝ : x ∈ {i, j}
hx : x ∈ {j}
⊢ (if x = i then t₁ else t₂) ∈ s x

tactic: simp [hx, ht₁]
state_before: case inl
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
x : ι
hx✝ : x ∈ {i, j}
hx : x = i
⊢ (if x = i then t₁ else t₂) ∈ s x
state_after: no goals

tactic: simp [Finset.mem_singleton.mp hx, hij.symm, ht₂]
state_before: case inr
α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
x : ι
hx✝ : x ∈ {i, j}
hx : x ∈ {j}
⊢ (if x = i then t₁ else t₂) ∈ s x
state_after: no goals

tactic: simp only [if_true, eq_self_iff_true]
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
⊢ t₁ = if i = i then t₁ else t₂
state_after: no goals

tactic: simp only [hij.symm, if_false]
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
⊢ t₂ = if j = i then t₁ else t₂
state_after: no goals

tactic: simp only [Finset.set_biInter_singleton, Finset.set_biInter_insert]
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
⊢ (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
state_after: no goals

tactic: simp only [hij, Finset.prod_singleton, Finset.prod_insert, not_false_iff,
  Finset.mem_singleton]
state_before: α : Type u_1
Ω : Type u_2
ι : Type u_3
_mα : MeasurableSpace α
s : ι → Set (Set Ω)
_mΩ : MeasurableSpace Ω
κ : ↥(kernel α Ω)
μ : Measure α
h_indep : iIndepSets s κ μ
i j : ι
hij : i ≠ j
t₁ t₂ : Set Ω
ht₁ : t₁ ∈ s i
ht₂ : t₂ ∈ s j
hf_m : ∀ x ∈ {i, j}, (if x = i then t₁ else t₂) ∈ s x
h1 : t₁ = if i = i then t₁ else t₂
h2 : t₂ = if j = i then t₁ else t₂
h_inter : (⋂ t ∈ {i, j}, if t = i then t₁ else t₂) = (if i = i then t₁ else t₂) ∩ if j = i then t₁ else t₂
a : α
h_indep' : (κ a) (⋂ i_1 ∈ {i, j}, if i_1 = i then t₁ else t₂) = ∏ i_1 ∈ {i, j}, (κ a) (if i_1 = i then t₁ else t₂)
⊢ ∏ t ∈ {i, j}, (κ a) (if t = i then t₁ else t₂) = (κ a) (if i = i then t₁ else t₂) * (κ a) (if j = i then t₁ else t₂)
state_after: no goals