`{!IsSurjInj F} : IsSurjInj (G o F) <-> IsSurjInj G. Proof. split; [ apply @cancelR_issurjinj | intros; apply @issurjinj_compose ]; exact _. Defined.
Require Import Basics.Overture Basics.Tactics Basics.Iff. Require Import WildCat.Core. Require Import WildCat.NatTrans. Require Import WildCat.Sigma.