Lemma idtoiso_postcompose (C : precategory) (a b b' : ob C) (p : b = b') (f : a --> b) : f · idtoiso p = transportf (λ b, a --> b) p f. Proof. destruct p. apply id_right. 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.