Lemma is_precategory_graph : is_precategory graph_precategory_data. Proof. apply is_precategory_one_assoc_to_two. repeat apply make_dirprod; cbn. - exact @graph_mor_id_left. - exact @graph_mor_id_right. - exact @graph_mor_comp_assoc. Qed.
Require Import UniMath.Foundations.PartB. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.Combinatorics.Graph.