proposition: Lemma allButLastCPTl {T:Type} {n:nat} : forall (cp : cartesianPower T (S (S (S n)))), allButLastCP (tailCP cp) = tailCP (allButLastCP cp).
proof: Proof. intro cp; induction n; simpl; reflexivity. Qed.
imports: Arith NArith List Sorting Coq.Program.Equality