English
The limit (in the category of rings) of a functor F: J ⥤ CommRingCat carries a canonical commutative ring structure.
Русский
Предел (в категории колец) диаграммы F : J ⥤ CommRingCat обладает естественной структурой коммутативного кольца.
LaTeX
$$$\mathrm{CommRingCat}.\text{limitCone } F\; \text{is a limit cone; its vertex carries a commutative ring}. $$$
Lean4
instance limitCommRing : CommRing.{u} (Types.Small.limitCone.{v, u} (F ⋙ forget CommRingCat.{u})).pt :=
let _ : CommRing (F ⋙ forget CommRingCat).sections :=
@Subring.toCommRing (∀ j, F.obj j) _ (RingCat.sectionsSubring.{v, u} (F ⋙ forget₂ CommRingCat RingCat.{u}))
inferInstanceAs <| CommRing (Shrink _)