have ⟨e, (_ : m + e ≃ 0)⟩ := le_defn.mp ‹m ≤ 0›
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
x✝ : m ≤ 0
⊢ n ≤ 0
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✝¹ : n + d ≃ m
x✝ : m ≤ 0
e : ℕ
h✝ : m + e ≃ 0
⊢ n ≤ 0