Definition pb_eqn {C:category} {a b c:C} {f:a-->c} {g:b-->c} (pb : Pullback f g) : f ∘ pb_1 pb = g ∘ pb_2 pb := pr2 (universalElement pb).
Require Import UniMath.Foundations.Preamble. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.Univalence. Require Import Require Import Require Import UniMath.MoreFoundations.Tactics.