apply Or.inr
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m : ℕ
x✝¹ : n ≤ m
d : ℕ
x✝ : n + 0 ≃ m
⊢ n < m ∨ n ≃ m
case h
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m : ℕ
x✝¹ : n ≤ m
d : ℕ
x✝ : n + 0 ≃ m
⊢ n ≃ m