Theorem: MeasureTheory.IsStoppingTime.measurableSet_eq_stopping_time_of_countable
File: Mathlib/Probability/Process/Stopping.lean

tactic: rw [hτ.measurableSet]
state_before: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
⊢ MeasurableSet {ω | τ ω = π ω}
state_after: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
⊢ ∀ (i : ι), MeasurableSet ({ω | τ ω = π ω} ∩ {ω | τ ω ≤ i})

tactic: intro j
state_before: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
⊢ ∀ (i : ι), MeasurableSet ({ω | τ ω = π ω} ∩ {ω | τ ω ≤ i})
state_after: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
⊢ MeasurableSet ({ω | τ ω = π ω} ∩ {ω | τ ω ≤ j})

tactic: rw [this]
state_before: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ MeasurableSet ({ω | τ ω = π ω} ∩ {ω | τ ω ≤ j})
state_after: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ MeasurableSet ({ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j})

tactic: refine
  MeasurableSet.inter (MeasurableSet.inter ?_ (hτ.measurableSet_le j)) (hπ.measurableSet_le j)
state_before: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ MeasurableSet ({ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j})
state_after: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ MeasurableSet {ω | min (τ ω) j = min (π ω) j}

tactic: apply measurableSet_eq_fun_of_countable
state_before: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ MeasurableSet {ω | min (τ ω) j = min (π ω) j}
state_after: case hf
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ Measurable fun x => min (τ x) j

case hg
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ Measurable fun x => min (π x) j

tactic: ext1 ω
state_before: Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
⊢ {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
state_after: case h
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
⊢ ω ∈ {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} ↔ ω ∈ {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}

tactic: simp only [Set.mem_inter_iff, Set.mem_setOf_eq]
state_before: case h
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
⊢ ω ∈ {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} ↔ ω ∈ {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
state_after: case h
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
⊢ τ ω = π ω ∧ τ ω ≤ j ↔ (min (τ ω) j = min (π ω) j ∧ τ ω ≤ j) ∧ π ω ≤ j

tactic: refine ⟨fun h => ⟨⟨?_, h.2⟩, ?_⟩, fun h => ⟨?_, h.1.2⟩⟩
state_before: case h
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
⊢ τ ω = π ω ∧ τ ω ≤ j ↔ (min (τ ω) j = min (π ω) j ∧ τ ω ≤ j) ∧ π ω ≤ j
state_after: case h.refine_1
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : τ ω = π ω ∧ τ ω ≤ j
⊢ min (τ ω) j = min (π ω) j

case h.refine_2
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : τ ω = π ω ∧ τ ω ≤ j
⊢ π ω ≤ j

case h.refine_3
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : (min (τ ω) j = min (π ω) j ∧ τ ω ≤ j) ∧ π ω ≤ j
⊢ τ ω = π ω

tactic: rw [h.1]
state_before: case h.refine_1
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : τ ω = π ω ∧ τ ω ≤ j
⊢ min (τ ω) j = min (π ω) j
state_after: no goals

tactic: rw [← h.1]
state_before: case h.refine_2
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : τ ω = π ω ∧ τ ω ≤ j
⊢ π ω ≤ j
state_after: case h.refine_2
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : τ ω = π ω ∧ τ ω ≤ j
⊢ τ ω ≤ j

tactic: exact h.2
state_before: case h.refine_2
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : τ ω = π ω ∧ τ ω ≤ j
⊢ τ ω ≤ j
state_after: no goals

tactic: cases' h with h' hπ_le
state_before: case h.refine_3
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h : (min (τ ω) j = min (π ω) j ∧ τ ω ≤ j) ∧ π ω ≤ j
⊢ τ ω = π ω
state_after: case h.refine_3.intro
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h' : min (τ ω) j = min (π ω) j ∧ τ ω ≤ j
hπ_le : π ω ≤ j
⊢ τ ω = π ω

tactic: cases' h' with h_eq hτ_le
state_before: case h.refine_3.intro
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
h' : min (τ ω) j = min (π ω) j ∧ τ ω ≤ j
hπ_le : π ω ≤ j
⊢ τ ω = π ω
state_after: case h.refine_3.intro.intro
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
hπ_le : π ω ≤ j
h_eq : min (τ ω) j = min (π ω) j
hτ_le : τ ω ≤ j
⊢ τ ω = π ω

tactic: rwa [min_eq_left hτ_le, min_eq_left hπ_le] at h_eq
state_before: case h.refine_3.intro.intro
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
ω : Ω
hπ_le : π ω ≤ j
h_eq : min (τ ω) j = min (π ω) j
hτ_le : τ ω ≤ j
⊢ τ ω = π ω
state_after: no goals

tactic: exact (hτ.min_const j).measurable_of_le fun _ => min_le_right _ _
state_before: case hf
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ Measurable fun x => min (τ x) j
state_after: no goals

tactic: exact (hπ.min_const j).measurable_of_le fun _ => min_le_right _ _
state_before: case hg
Ω : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace Ω
inst✝⁷ : LinearOrder ι
f : Filtration ι m
τ π : Ω → ι
inst✝⁶ : Countable ι
inst✝⁵ : TopologicalSpace ι
inst✝⁴ : MeasurableSpace ι
inst✝³ : BorelSpace ι
inst✝² : OrderTopology ι
inst✝¹ : MeasurableSingletonClass ι
inst✝ : SecondCountableTopology ι
hτ : IsStoppingTime f τ
hπ : IsStoppingTime f π
j : ι
this : {ω | τ ω = π ω} ∩ {ω | τ ω ≤ j} = {ω | min (τ ω) j = min (π ω) j} ∩ {ω | τ ω ≤ j} ∩ {ω | π ω ≤ j}
⊢ Measurable fun x => min (π x) j
state_after: no goals