{A} `{Is1Cat A} {x y : A} (f : x $-> y) {bif : Cat_IsBiInv f} : cat_equiv_inv f $o f $== Id x := (cat_inverses_homotopic f $@R f) $@ ' f.
Require Import Basics.Utf8 Basics.Overture Basics.Tactics Basics.Equivalences. Require Import WildCat.Core. Require Import WildCat.Opposite.