have : n > m := pos_diff_gt.mp ‹Positive (n——m)›
ℕ : Type
inst✝ : Natural ℕ
n m : ℕ
x✝ : Positive (n——m)
⊢ (n——m).sgn ≃ 1
ℕ : Type
inst✝ : Natural ℕ
n m : ℕ
x✝ : Positive (n——m)
this : n > m
⊢ (n——m).sgn ≃ 1