fact: Definition to_postmor (x : PA) {y z : PA} (f : y --> z) : to_abgr x y -> to_abgr x z := fun (g : (to_abgr x y)) => g · f.
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