proposition: Lemma isgrop_ringofendabgr_op1 {G : abgr} : isgrop (@ringofendabgr_op1 G).
proof: Proof. exact (make_isgrop ismonoidop_ringofendabgr_op1 invstruct_setofendabgr_inv). Defined.
imports: UniMath.MoreFoundations.Tactics UniMath.Algebra.RigsAndRings UniMath.Algebra.Groups UniMath.Algebra.Monoids