{A} `{HasEquivs A} {a b c : A} (e : a $<~> b) (f : a $-> c) (g : b $-> c) (p : f $o e^-1$ $== g) : f $== g $o e. Proof. apply (cate_epic_equiv e^-1$). exact (p $@ (compose_hh_V _ _)^$). Defined.
Require Import Basics.Utf8 Basics.Overture Basics.Tactics Basics.Equivalences. Require Import WildCat.Core. Require Import WildCat.Opposite.