Definition identity_matrix {C:category} (h:ZeroMaps C) {I} (d:I -> ob C) (dec : isdeceq I) : ∏ i j, Hom C (d j) (d i). Proof. intros. induction (dec i j) as [ eq | ne ]. { induction eq. apply identity. } { apply h. } Defined.
Require Import UniMath.Foundations.All. Require Import UniMath.MoreFoundations.All. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.Core.Univalence. Require Import