Definition two_of_three {C : category} (W : morph_class C) := ∏ (x y z : C) (f : x --> y) (g : y --> z), (W _ _ f × W _ _ g -> W _ _ (f · g)) × (W _ _ f × W _ _ (f · g) -> W _ _ g) × (W _ _ g × W _ _ (f · g) -> W _ _ f).
Require Import UniMath.Foundations.All. Require Import UniMath.MoreFoundations.All. Require Import UniMath.CategoryTheory.Monics. Require Import UniMath.CategoryTheory.Epis. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.Isos.