proposition: Lemma functor_full_img_essentially_surjective (A B : category) (F : functor A B) : essentially_surjective (functor_full_img F).
proof: Proof. intro b. use (pr2 b). intros [c h] q Hq. apply Hq. exists c. apply iso_in_sub_from_iso. apply h. Qed.
imports: UniMath.Foundations.Sets UniMath.MoreFoundations.PartA UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Subcategory.Core