-- Mathlib/Probability/Independence/Conditional.lean
theorem condIndepSets_singleton_iff {μ : Measure Ω} [IsFiniteMeasure μ]
    {s t : Set Ω} (hs : MeasurableSet s) (ht : MeasurableSet t) :
    CondIndepSets m' hm' {s} {t} μ ↔ (μ⟦s ∩ t | m'⟧) =ᵐ[μ] (μ⟦s | m'⟧) * (μ⟦t | m'⟧)

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' = s
⊢ MeasurableSet s'

Tactic:
rwa [hs']

Result:
no goals

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
⊢ ∀ s_1 ∈ {s}, MeasurableSet s_1

Tactic:
intros s' hs'

Result:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' ∈ {s}
⊢ MeasurableSet s'

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
⊢ (∀ (t1 t2 : Set Ω),
      t1 ∈ {s} →
        t2 ∈ {t} →
          μ[(t1 ∩ t2).indicator fun ω => 1|m'] =ᶠ[ae μ] μ[t1.indicator fun ω => 1|m'] * μ[t2.indicator fun ω => 1|m']) ↔
    μ[(s ∩ t).indicator fun ω => 1|m'] =ᶠ[ae μ] μ[s.indicator fun ω => 1|m'] * μ[t.indicator fun ω => 1|m']

Tactic:
simp only [Set.mem_singleton_iff, forall_eq_apply_imp_iff, forall_eq]

Result:
no goals

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' ∈ {t}
⊢ MeasurableSet s'

Tactic:
rw [Set.mem_singleton_iff] at hs'

Result:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' = t
⊢ MeasurableSet s'

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
⊢ ∀ s ∈ {t}, MeasurableSet s

Tactic:
intros s' hs'

Result:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' ∈ {t}
⊢ MeasurableSet s'

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
⊢ CondIndepSets m' hm' {s} {t} μ ↔
    μ[(s ∩ t).indicator fun ω => 1|m'] =ᶠ[ae μ] μ[s.indicator fun ω => 1|m'] * μ[t.indicator fun ω => 1|m']

Tactic:
rw [condIndepSets_iff _ _ _ _ ?_ ?_]

Result:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
⊢ (∀ (t1 t2 : Set Ω),
      t1 ∈ {s} →
        t2 ∈ {t} →
          μ[(t1 ∩ t2).indicator fun ω => 1|m'] =ᶠ[ae μ] μ[t1.indicator fun ω => 1|m'] * μ[t2.indicator fun ω => 1|m']) ↔
    μ[(s ∩ t).indicator fun ω => 1|m'] =ᶠ[ae μ] μ[s.indicator fun ω => 1|m'] * μ[t.indicator fun ω => 1|m']

Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
⊢ ∀ s_1 ∈ {s}, MeasurableSet s_1

Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
⊢ ∀ s ∈ {t}, MeasurableSet s

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' ∈ {s}
⊢ MeasurableSet s'

Tactic:
rw [Set.mem_singleton_iff] at hs'

Result:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' = s
⊢ MeasurableSet s'

Proof state:
Ω : Type u_1
m' mΩ : MeasurableSpace Ω
inst✝¹ : StandardBorelSpace Ω
hm' : m' ≤ mΩ
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
s t : Set Ω
hs : MeasurableSet s
ht : MeasurableSet t
s' : Set Ω
hs' : s' = t
⊢ MeasurableSet s'

Tactic:
rwa [hs']

Result:
no goals