Lemma isiso_from_Pullback_to_Pullback {a b c : C} {f : C⟦b, a⟧} {g : C⟦c, a⟧} (Pb Pb': Pullback f g) : is_iso (from_Pullback_to_Pullback Pb Pb'). Proof. apply (is_iso_qinv _ (from_Pullback_to_Pullback Pb' Pb)). apply are_inverses_from_Pullback_to_Pullback. Defined.
Require Import UniMath.Foundations.PartD. Require Import UniMath.Foundations.Propositions. Require Import UniMath.Foundations.Sets. Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.Combinatorics.StandardFiniteSets. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Univalence. Require Import UniMath.CategoryTheory.Limits.Graphs.Limits. Require Import UniMath.CategoryTheory.Limits.Graphs.Colimits.