proposition: Lemma linvax {x y : PA} (f : PA⟦x, y⟧) : to_binop x y (to_inv f) f = to_unel x y.
proof: Proof. apply (grlinvax (to_abgr x y)). Qed.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.PrecategoryBinProduct UniMath.CategoryTheory.CategoriesWithBinOps UniMath.CategoryTheory.opp_precat UniMath.CategoryTheory.Core.Functors