proposition: Lemma is_functor_cgraph_forget : @is_functor cgraph_precategory hset_precategory cgraph_forget_data.
proof: Proof. apply make_dirprod. - intro x. cbn. apply idpath. - intros x y z. cbn. intros f g. apply idpath. Qed.
imports: UniMath.Foundations.PartA UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Categories.HSET.Core UniMath.Combinatorics.CGraph