Definition CPToList {T:Type} {n:nat} (cp : cartesianPower T n) : list T.

Lemma lastCPIn {T:Type} {n:nat} : forall (cp : cartesianPower T (S n)), InCP (lastCP cp) cp.
Definition nthCP {T:Type} {m:nat} (n : nat) (cp : cartesianPower T m) (Default : T) := nth (n-1) (CPToList cp) Default.