{A} {P Q : A -> Type} (f : forall a, P a -> Q a) (C : sig Q -> Type) (ef : forall a, ooExtendableAlong (f a) (fun v => C (a;v))) : ooExtendableAlong (functor_sigma idmap f) C := fun n => extendable_functor_sigma_id n f C (fun a => ef a n).
Require Import HoTT.Basics HoTT.Types. Require Import Equiv.PathSplit Homotopy.IdentitySystems. Require Import Cubical.DPath Cubical.DPathSquare. Require Import Colimits.Coeq Colimits.MappingCylinder.