cyl_ooextendable' {A B} (f : A -> B) (C : B -> Type) (ext : ooExtendableAlong f C) : ooExtendableAlong cyl (C o (pr_cyl' f)) := fun n => cyl_extendable' n f C (ext 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.