{A} `{HasEquivs A} {a b c : A} (f : b $-> c) (g : a $<~> b) : (f $o g) $o g^-1$ $== f := cat_assoc _ _ _ $@ (f $@L cate_isretr g) $@ cat_idr f.
Require Import Basics.Utf8 Basics.Overture Basics.Tactics Basics.Equivalences. Require Import WildCat.Core. Require Import WildCat.Opposite.