Definition lastCP {T:Type} {n:nat} (cp : cartesianPower T (S n)) : T.

(* Specifications: *)
Lemma lastCPTl {T:Type} {n:nat} : forall (cp : cartesianPower T (S (S n))), lastCP cp = lastCP (tailCP cp).
Lemma CP_ind {T:Type} {n : nat} : forall (cp cp' : cartesianPower T (S (S n))), headCP cp = headCP cp' -> tailCP cp = tailCP cp' -> cp = cp'.