fact: Definition nattrans_comp {A B : Type} {F G K : A -> B} `{IsGraph A, Is1Cat B, !Is0Functor F, !Is0Functor G, !Is0Functor K} : NatTrans G K -> NatTrans F G -> NatTrans F K.
imports: Basics.Overture Basics.Tactics WildCat.Core WildCat.Equiv WildCat.Square