intro n₂ (_ : 0 ≃ step n₂)
ℕ : Type
inst✝⁵ : Core ℕ
inst✝⁴ : Induction ℕ
inst✝³ : Addition ℕ
inst✝² : Sign ℕ
inst✝¹ : Order ℕ
inst✝ : Multiplication ℕ
n₁ n₂✝ m n₂ : ℕ
⊢ ∀ (m_1 : ℕ), 0 ≃ step m_1 → 0 * m ≃ step m_1 * m
ℕ : Type
inst✝⁵ : Core ℕ
inst✝⁴ : Induction ℕ
inst✝³ : Addition ℕ
inst✝² : Sign ℕ
inst✝¹ : Order ℕ
inst✝ : Multiplication ℕ
n₁ n₂✝¹ m n₂✝ n₂ : ℕ
x✝ : 0 ≃ step n₂
⊢ 0 * m ≃ step n₂ * m