Lemma is_iso_lassociator {a b c d : C} (f : hom_precategory a b) (g : hom_precategory b c) (h : hom_precategory c d) : is_iso (lassociator f g h : (hom_precategory a d) ⟦ f · (g · h), (f · g) · h ⟧). Proof. apply is_iso_from_is_z_iso. apply is_z_iso_lassociator. Defined.
Require Import UniMath.Foundations.All. Require Import UniMath.MoreFoundations.All. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.PrecategoryBinProduct.