proposition: Lemma isassoc_ringofendabgr_op1 {G : abgr} : isassoc (@ringofendabgr_op1 G).
proof: Proof. intros f g h. use total2_paths_f. - apply funextfun. intro. apply (pr2 G). - apply isapropismonoidfun. Defined.
imports: UniMath.MoreFoundations.Tactics UniMath.Algebra.RigsAndRings UniMath.Algebra.Groups UniMath.Algebra.Monoids