open import Chapter2.Desc
open import Chapter2.Desc.Fixpoint
open import Chapter2.Desc.Lifting
open import Chapter2.Desc.Induction

module Chapter4.Case 
         (D : Desc)
         (P : μ D  Set)
       where

case : ((xs :  D  (μ D))  P  xs )  (x : μ D)  P x
case cases = induction D P  {xs} _  cases xs)