English
The Monoid instance on Germ_l M is determined by the Monoid structure on M, via the germ construction.
Русский
Экземпляр моноида на Germ_l M задаётся структурой моноида на M через конструкцию жермов.
LaTeX
$$$\\text{Monoid}(M) \\Rightarrow \\text{Germ}_lM\\text{ is a Monoid with the induced operations.}$$$
Lean4
@[to_additive]
instance instMonoid [Monoid M] : Monoid (Germ l M) :=
{
Function.Surjective.monoid ofFun Quot.mk_surjective (by rfl) (fun _ _ => by rfl) fun _ _ => by
rfl with
toSemigroup := instSemigroup
toOne := instOne
npow := fun n a => a ^ n }