∀ {R : Type u} [inst : Lean.Grind.Ring R] [inst_1 : LE R] [inst_2 : LT R] [Std.LawfulOrderLT R]
  [inst_4 : Std.IsLinearOrder R] [Lean.Grind.OrderedRing R] {a b : R}, 0 < a * b ↔ 0 < a ∧ 0 < b ∨ a < 0 ∧ b < 0