proposition: Lemma cone_prop (a : Cone) : ∏ j j' (f : j --> j'), ConeMor a j · #F f = ConeMor a j'.
proof: Proof. exact (pr2 a). Qed.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.MoreFoundations.PartA UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Functors