Lemma grfromgtunel (X : gr) {R : hrel X} (is : isbinophrel R) {x : X} (isg : R x 1) : R 1 (x^-1). Proof. intros. set (r := (pr2 is) _ _ (x^-1) isg). rewrite (grrinvax X x) in r. rewrite (lunax X _) in r. apply r. Defined.
Require Import UniMath.MoreFoundations.Subtypes.