English
Let V be a category and G a monoid. The category of actions of G in V is equivalent to the functor category from the one-object category associated to G to V.
Русский
Пусть V – категория, G – моноид. Категория действий G над V эквивалентна категории функторов из однобазовой категории, связанной с G, в V.
LaTeX
$$$\\mathrm{Action}(V,G) \\simeq \\mathrm{Fun}(\\mathrm{SingleObj}(G), V)$$$
Lean4
/-- The category of actions of `G` in the category `V`
is equivalent to the functor category `singleObj G ⥤ V`.
-/
@[simps]
def functorCategoryEquivalence : Action V G ≌ SingleObj G ⥤ V
where
functor := functor
inverse := inverse
unitIso := unitIso
counitIso := counitIso