proposition: Lemma isunital_ringofendabgr_op1 {G : abgr} : isunital (@ringofendabgr_op1 G).
proof: Proof. exact (make_isunital setofendabgr_un0 isunit_setofendabgr_un0). Defined.
imports: UniMath.MoreFoundations.Tactics UniMath.Algebra.RigsAndRings UniMath.Algebra.Groups UniMath.Algebra.Monoids