intro k (ih : m ≤ k → n ≤ k) (_ : m ≤ step k)
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m k : ℕ
x✝ : n ≤ m
d : ℕ
h✝ : n + d ≃ m
⊢ ∀ (m_1 : ℕ), (m ≤ m_1 → n ≤ m_1) → m ≤ step m_1 → n ≤ step m_1
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m k✝ : ℕ
x✝¹ : n ≤ m
d : ℕ
h✝ : n + d ≃ m
k : ℕ
ih : m ≤ k → n ≤ k
x✝ : m ≤ step k
⊢ n ≤ step k