English
There exists a commutative monoid structure on a set G given exponent G = 2.
Русский
Существует коммутативная структура моноида на множестве G при условии exp(G)=2.
LaTeX
$$$\text{commMonoidOfExponentTwo }(G) : \text{CommMonoid } G\text{ given } \operatorname{exponent} G = 2$$$
Lean4
/-- Any cancellative monoid of exponent two is abelian. -/
@[to_additive /-- Any additive group of exponent two is abelian. -/
]
abbrev commMonoidOfExponentTwo [IsCancelMul G] (hG : Monoid.exponent G = 2) : CommMonoid G where
mul_comm := mul_comm_of_exponent_two hG