intro (_ : 0 + m ≃ 0 + k)
ℕ : Type
inst✝² : Core ℕ
inst✝¹ : Induction ℕ
inst✝ : Addition ℕ
n m k : ℕ
⊢ 0 + m ≃ 0 + k → m ≃ k
ℕ : Type
inst✝² : Core ℕ
inst✝¹ : Induction ℕ
inst✝ : Addition ℕ
n m k : ℕ
x✝ : 0 + m ≃ 0 + k
⊢ m ≃ k