fact: Definition dcat_postcomp {A : Type} {D : A -> Type} `{IsD01Cat A D} {a b c : A} {g : b $-> c} {a' : D a} {b' : D b} {c' : D c} (g' : DHom g b' c') : forall (f : a $-> b), DHom f a' b' -> DHom (g $o f) a' c' := fun _ f' => g' $o' f'.
imports: Basics.Overture Basics.PathGroupoids Basics.Tactics Types.Sigma WildCat.Core WildCat.Prod