Theorem: LO.FirstOrder.Semiformula.neg_neg (Logic/FirstOrder/Basic/Syntax/Formula.lean)

State before:
L : Language
L₁ : Language
L₂ : Language
L₃ : Language
ξ : Type u_1
ξ₁ : Type u_2
ξ₂ : Type u_3
ξ₃ : Type u_4
n n₁ n₂✝ n₂ m m₁ m₂ m₃ : ℕ
p : Semiformula L ξ n
⊢ p.neg.neg = p
Tactic:
induction p <;> simp[*, neg]
State after:
no goals