Theorem: MeasurableSpace.injective_mapNatBool
File: Mathlib/MeasureTheory/MeasurableSpace/CountablyGenerated.lean

tactic: intro x y hxy
state_before: α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
⊢ Injective (mapNatBool α)
state_after: α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
⊢ x = y

tactic: rw [← generateFrom_natGeneratingSequence α] at *
state_before: α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
⊢ x = y
state_after: α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
⊢ x = y

tactic: apply separating_of_generateFrom (range (natGeneratingSequence _))
state_before: α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
⊢ x = y
state_after: case a
α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
⊢ ∀ s ∈ range (natGeneratingSequence α), x ∈ s ↔ y ∈ s

tactic: rintro - ⟨n, rfl⟩
state_before: case a
α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
⊢ ∀ s ∈ range (natGeneratingSequence α), x ∈ s ↔ y ∈ s
state_after: case a.intro
α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ x ∈ natGeneratingSequence α n ↔ y ∈ natGeneratingSequence α n

tactic: rw [← decide_eq_decide]
state_before: case a.intro
α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ x ∈ natGeneratingSequence α n ↔ y ∈ natGeneratingSequence α n
state_after: case a.intro
α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ decide (x ∈ natGeneratingSequence α n) = decide (y ∈ natGeneratingSequence α n)

α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ Decidable (x ∈ natGeneratingSequence α n)

α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ Decidable (y ∈ natGeneratingSequence α n)

tactic: exact congr_fun hxy n
state_before: case a.intro
α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ decide (x ∈ natGeneratingSequence α n) = decide (y ∈ natGeneratingSequence α n)

α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ Decidable (x ∈ natGeneratingSequence α n)

α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : CountablyGenerated α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
x y : α
hxy : mapNatBool α x = mapNatBool α y
n : ℕ
⊢ Decidable (y ∈ natGeneratingSequence α n)
state_after: no goals