Remark wellFormedTermTermsCorrect2 :
 forall n : nat,
 (wellFormedTerm n <> 0 -> exists t : Term, codeTerm L codeF t = n) /\
 (wellFormedTerms n <> 0 ->
  exists m : nat, (exists ts : Terms m, codeTerms L codeF m ts = n)).

Lemma wellFormedTermCorrect2 : forall n : nat, wellFormedTerm n <> 0 -> exists t : Term, codeTerm L codeF t = n.