Definition Under_comp (X Y Z : Under_ob) : Under_mor X Y -> Under_mor Y Z -> Under_mor X Z. Proof. intros f g. exact (make_Under_mor X Z (Under_mor_mor f · Under_mor_mor g) (Under_comp_eq f g)). 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.