English
If α is a Monoid with IsMulTorsionFree, then AddOpposite α is IsMulTorsionFree.
Русский
Если у α имеется свойство IsMulTorsionFree, то AddOpposite α также имеет это свойство.
LaTeX
$$$\\text{IsMulTorsionFree}(\\alpha) \\Rightarrow \\text{IsMulTorsionFree}(\\alpha^{\\mathrm{op}})$$$
Lean4
@[to_additive]
instance group [∀ i, Group (f i)] : Group (∀ i, f i) where inv_mul_cancel := by intros; ext; exact inv_mul_cancel _