Theorem: MeasureTheory.dirac_ne_dirac_iff_exists_measurableSet
File: Mathlib/MeasureTheory/Measure/Dirac.lean

tactic: apply not_iff_not.mp
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
⊢ dirac x ≠ dirac y ↔ ∃ A, MeasurableSet A ∧ x ∈ A ∧ y ∉ A
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
⊢ ¬dirac x ≠ dirac y ↔ ¬∃ A, MeasurableSet A ∧ x ∈ A ∧ y ∉ A

tactic: simp only [ne_eq, not_not, not_exists, not_and, dirac_eq_dirac_iff_forall_mem_iff_mem]
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
⊢ ¬dirac x ≠ dirac y ↔ ¬∃ A, MeasurableSet A ∧ x ∈ A ∧ y ∉ A
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
⊢ (∀ (A : Set α), MeasurableSet A → (x ∈ A ↔ y ∈ A)) ↔ ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1

tactic: refine ⟨fun h A A_mble ↦ by simp only [h A A_mble, imp_self], fun h A A_mble ↦ ?_⟩
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
⊢ (∀ (A : Set α), MeasurableSet A → (x ∈ A ↔ y ∈ A)) ↔ ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
h : ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
A : Set α
A_mble : MeasurableSet A
⊢ x ∈ A ↔ y ∈ A

tactic: by_cases x_in_A : x ∈ A
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
h : ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
A : Set α
A_mble : MeasurableSet A
⊢ x ∈ A ↔ y ∈ A
state_after: case pos
α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
h : ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
A : Set α
A_mble : MeasurableSet A
x_in_A : x ∈ A
⊢ x ∈ A ↔ y ∈ A

case neg
α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
h : ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
A : Set α
A_mble : MeasurableSet A
x_in_A : x ∉ A
⊢ x ∈ A ↔ y ∈ A

tactic: simp only [h A A_mble, imp_self]
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
h : ∀ (A : Set α), MeasurableSet A → (x ∈ A ↔ y ∈ A)
A : Set α
A_mble : MeasurableSet A
⊢ x ∈ A → y ∈ A
state_after: no goals

tactic: simp only [x_in_A, h A A_mble x_in_A]
state_before: case pos
α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
h : ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
A : Set α
A_mble : MeasurableSet A
x_in_A : x ∈ A
⊢ x ∈ A ↔ y ∈ A
state_after: no goals

tactic: simpa only [x_in_A, false_iff] using h Aᶜ (MeasurableSet.compl_iff.mpr A_mble) x_in_A
state_before: case neg
α : Type u_1
β : Type u_2
δ : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
s : Set α
a x y : α
h : ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
A : Set α
A_mble : MeasurableSet A
x_in_A : x ∉ A
⊢ x ∈ A ↔ y ∈ A
state_after: no goals