Definition codeClose (f : nat) : nat :=
  codeCloseList (codeNoDup (codeFreeVarFormula f)) f.

(* Specifications: *)
Lemma codeCloseCorrect : forall f : Formula, codeClose (codeFormula f) = codeFormula (close L f).
Lemma codeCloseIsPR : isPR 1 codeClose.