have : sgn a ≃ 1 := Rel.trans ‹sgn a ≃ sgn b› ‹sgn b ≃ 1›
ℚ : Type
inst✝ : Rational ℚ
x : ℚ
x✝ : Positive x
a b : Integer.Impl.Difference ℕ
b_nonzero✝ : Nonzero b
x_eqv : x ≃ Rational.from_integer a / Rational.from_integer b
this✝¹ : x ≃ Rational.from_integer a / Rational.from_integer b
this✝ : sgn a * sgn b ≃ 1
left✝ : Integer.Sqrt1 (sgn b)
right✝ : sgn a ≃ sgn b
this : sgn b ≃ 1 ∨ sgn b ≃ -1
h✝ : sgn b ≃ 1
⊢ AltPositive x
ℚ : Type
inst✝ : Rational ℚ
x : ℚ
x✝ : Positive x
a b : Integer.Impl.Difference ℕ
b_nonzero✝ : Nonzero b
x_eqv : x ≃ Rational.from_integer a / Rational.from_integer b
this✝² : x ≃ Rational.from_integer a / Rational.from_integer b
this✝¹ : sgn a * sgn b ≃ 1
left✝ : Integer.Sqrt1 (sgn b)
right✝ : sgn a ≃ sgn b
this✝ : sgn b ≃ 1 ∨ sgn b ≃ -1
h✝ : sgn b ≃ 1
this : sgn a ≃ 1
⊢ AltPositive x