Lemma idtoiso_precompose (C : precategory) (a a' b : ob C) (p : a = a') (f : a --> b) : (idtoiso (!p)) · f = transportf (λ a, a --> b) p f. Proof. destruct p. apply id_left. Qed.
Require Import UniMath.Foundations.PartA. Require Import UniMath.Foundations.Sets. Require Import UniMath.MoreFoundations.PartA. Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos.