{A B : Type} (C : B -> Type) (f : A -> B) (h k : forall b, C b) : ooExtendableAlong f C -> ooExtendableAlong f (fun b => h b = k b). Proof. intros ext n; apply extendable_homotopy, ext. Defined.
Require Import HoTT.Basics HoTT.Types. Require Import Equiv.PathSplit Homotopy.IdentitySystems. Require Import Cubical.DPath Cubical.DPathSquare. Require Import Colimits.Coeq Colimits.MappingCylinder.