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