Definition Equalizer {y z : C} (f g : y --> z) : UU := ∑ e : (∑ w : C, w --> y), (∑ H : (pr2 e) · f = (pr2 e) · g, isEqualizer f g (pr2 e) H).
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.Univalence. Require Import UniMath.CategoryTheory.Monics. Require Import UniMath.CategoryTheory.Retracts.