English
The inverse of the restriction inverse app equals the c-component composed with a presheaf map.
Русский
Обратное ограниченного invApp соответствует композиции с c-компонентом и отображением на предшехе.
LaTeX
$$inv (H.invApp U) = f.c.app (op (opensFunctor f |>.obj U)) ≫ X.presheaf.map (eqToHom (by simp [Opens.map, Set.preimage_image_eq _ H.base_open.injective]))$$
Lean4
theorem inv_invApp (U : Opens X) :
inv (H.invApp _ U) =
f.c.app (op (opensFunctor f |>.obj U)) ≫
X.presheaf.map (eqToHom (by simp [Opens.map, Set.preimage_image_eq _ H.base_open.injective])) :=
by
rw [← cancel_epi (H.invApp _ U), IsIso.hom_inv_id]
delta invApp
simp [← Functor.map_comp]