English
For any f: Quot F →+ A and hc IsColimit of c, the value of hc.desc(toCocone F f) at Quot.desc F c x equals f x for any x ∈ Quot F.
Русский
Для любого f: Quot F →+ A и hc, являющегося IsColimit для c, значение hc.desc(toCocone F f) на Quot.desc F c x равно f x для любого x ∈ Quot F.
LaTeX
$$$ (hc.desc (toCocone F f)).hom (Quot.desc F c x) = f x $$$
Lean4
theorem desc_quotQuotUliftAddEquiv [DecidableEq J] (c : Cocone F) :
(Quot.desc (F ⋙ uliftFunctor.{u'}) (uliftFunctor.{u'}.mapCocone c)).comp (quotQuotUliftAddEquiv F).toAddMonoidHom =
AddEquiv.ulift.symm.toAddMonoidHom.comp (Quot.desc F c) :=
by
refine Quot.addMonoidHom_ext _ (fun j a ↦ ?_)
dsimp
simp only [quotToQuotUlift_ι, Functor.comp_obj, uliftFunctor_obj, ι_desc, Functor.const_obj_obj, ι_desc]
erw [Quot.ι_desc]
rfl