Definition natToTermLNN := LNN.natToTerm.Definition natToTermLNT := LNT.natToTerm.Definition codeNatToTerm : nat -> nat :=
  nat_rec (fun _ => nat) (cPair 4 0)
    (fun _ rec : nat => cPair 3 (S (cPair rec 0))).

Lemma codeNatToTermIsPR : isPR 1 codeNatToTerm.