Lemma islinv_setofendabgr_inv {G : abgr} : islinv (@ringofendabgr_op1 G) (unel_is (@ismonoidop_ringofendabgr_op1 G)) setofendabgr_inv. Proof. intro f. use total2_paths_f. - apply funextfun. intro x. apply (grlinvax G). - apply isapropismonoidfun. Defined.
Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.Algebra.RigsAndRings. Require Import UniMath.Algebra.Groups. Require Import UniMath.Algebra.Monoids.