Definition Under_precategories_mor_functor_data {c c' : C} (h : C⟦c, c'⟧) : functor_data (c' / C) (c / C). Proof. exists (Under_precategories_mor_ob h). exact (Under_precategories_mor_mor h). Defined.
Require Import UniMath.Foundations.PartD. Require Import UniMath.Foundations.Propositions. Require Import UniMath.Foundations.Sets. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Functors.