exact this
ℕ : Type
inst✝ : Natural ℕ
n m : ℕ
x✝ : Negative (n——m)
this✝³ : n < m
this✝² : compare n m = Ordering.lt
this✝¹ : ord_sgn (compare n m) ≃ ord_sgn Ordering.lt
this✝ : ord_sgn (compare n m) ≃ -1
this : (n——m).sgn ≃ -1
⊢ (n——m).sgn ≃ -1
no goals