Definition codeSysPrfNot :=
  existH 2
    (andH (substituteFormula LNN codeSysPrf 0 (var 2))
       (substituteFormula LNN
          (substituteFormula LNN (primRecFormula 1 (proj1_sig codeNotIsPR)) 0
             (var 2)) 1 (var 0))).

Lemma freeVarCodeSysPrfN : forall v : nat, In v (freeVarFormula LNN codeSysPrfNot) -> v <= 1.