proposition: Lemma gr_equiv_iso (X Y : ob gr_category) : monoidiso (X : gr) (Y : gr) -> z_iso X Y.
proof: Proof. intros f. exact (_,,gr_equiv_is_iso X Y f). Defined.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.Foundations.UnivalenceAxiom UniMath.Algebra.BinaryOperations UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Functors