English
The canonical map from R to Localization Away(1) is an isomorphism in the category of commutative rings (since inverting 1 yields no change).
Русский
Каноническое отображение из R в Localization Away(1) является изоморфизмом в категории коммутативных колец.
LaTeX
$$$\mathrm{IsIso}\big(\text{algebraMap } R \; (\mathrm{Localization Away}(1))\big)$$$
Lean4
instance localization_unit_isIso (R : CommRingCat) :
IsIso (CommRingCat.ofHom <| algebraMap R (Localization.Away (1 : R))) :=
Iso.isIso_hom (IsLocalization.atOne R (Localization.Away (1 : R))).toRingEquiv.toCommRingCatIso