proposition: Lemma isunit_setofendabgr_un0 {G : abgr} : isunit (@ringofendabgr_op1 G) setofendabgr_un0.
proof: Proof. exact (make_isunit islunit_setofendabgr_un0 isrunit_setofendabgr_un0). Defined.
imports: UniMath.MoreFoundations.Tactics UniMath.Algebra.RigsAndRings UniMath.Algebra.Groups UniMath.Algebra.Monoids