English
The torsion submonoid of a commutative monoid is torsion.
Русский
Торовая подплощадь коммутативного моноида является торсовой.
LaTeX
$$IsTorsion (torsion G)$$
Lean4
/-- The torsion submonoid of a commutative monoid.
(Note that by `Monoid.IsTorsion.group` torsion monoids are truthfully groups.)
-/
@[to_additive addTorsion /-- The torsion submonoid of an additive commutative monoid. -/
]
def torsion : Submonoid G where
carrier := {x | IsOfFinOrder x}
one_mem' := IsOfFinOrder.one
mul_mem' hx hy := hx.mul hy