English
A sigma-form characterization of multiplication: there exist Ore witnesses r', s' such that s' * r₁ = r' * s₂ and r₁ /ₒ s₁ * (r₂ /ₒ s₂) = r' * r₂ /ₒ (s' * s₁).
Русский
Сигма-форма характеристики умножения: существуют свидетели Оре r', s' такие, что s'·r₁ = r'·s₂ и r₁ /ₒ s₁ * (r₂ /ₒ s₂) = r' · r₂ /ₒ (s' · s₁).
LaTeX
$$$ (r_1 /ₒ s_1) * (r_2 /ₒ s_2) = r' * r_2 /ₒ (s' * s_1) \quad \text{with } s' * r_1 = r' * s_2 $$$
Lean4
@[to_additive]
protected theorem one_mul (x : R[S⁻¹]) : 1 * x = x :=
OreLocalization.one_smul x