exact AA.substFn ‹-a - -b ≃ b - a› ‹Positive (-a - -b)›
ℕ : Type
inst✝⁷ : Natural ℕ
ℤ : Type
inst✝⁶ : Core ℤ
inst✝⁵ : Addition ℤ
inst✝⁴ : Multiplication ℤ
inst✝³ : Negation ℤ
inst✝² : Subtraction ℤ
inst✝¹ : Sign ℤ
inst✝ : Order ℤ
a b : ℤ
this✝ : -a - -b ≃ b - a
x✝ : -b < -a
this : Positive (-a - -b)
⊢ Positive (b - a)
no goals