English
Naturality of iso_hom in CatCommSqOver with respect to a morphism f in X: the natural transformation hom respects the map between F and G via the isomorphism S.iso.hom.
Русский
Естественность гомоморфизма изоморфии в CatCommSqOver по отношению к морфизму f в X: натуральное преобразование гомоморфизма сохраняет связь между F и G через S.iso.hom.
LaTeX
$$$ S.iso.hom.naturality f$$$
Lean4
/-- Comparing mkNatIso with the corresponding construction one can deduce from
`functorEquiv`. -/
theorem mkNatIso_eq :
mkNatIso e₁ e₂ coh =
(functorEquiv F G X).fullyFaithfulFunctor.preimageIso
(CategoricalPullback.mkIso e₁ e₂ (by simpa [functorEquiv, toCatCommSqOver] using coh)) :=
by
rw [← toCatCommSqOver_mapIso_mkNatIso_eq_mkIso e₁ e₂ coh]
dsimp [Equivalence.fullyFaithfulFunctor]
cat_disch