fact: Definition 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).
imports: HoTT.Basics HoTT.Types Equiv.PathSplit PathAny Cubical.DPath Cubical.DPathSquare Colimits.Coeq Colimits.MappingCylinder