intro n (ih : n + m ≃ n + k → m ≃ k) (_ : step n + m ≃ step n + k)
ℕ : Type
inst✝² : Core ℕ
inst✝¹ : Induction ℕ
inst✝ : Addition ℕ
n m k : ℕ
⊢ ∀ (m_1 : ℕ), (m_1 + m ≃ m_1 + k → m ≃ k) → step m_1 + m ≃ step m_1 + k → m ≃ k
ℕ : Type
inst✝² : Core ℕ
inst✝¹ : Induction ℕ
inst✝ : Addition ℕ
n✝ m k n : ℕ
ih : n + m ≃ n + k → m ≃ k
x✝ : step n + m ≃ step n + k
⊢ m ≃ k