// Check the input signature
 public void checkInputSignature(ATermList sigs) {
   while (!sigs.isEmpty()) {
     ATermAppl sig = (ATermAppl) sigs.getFirst();
     sigs = sigs.getNext();
     if (!sigTable.containsKey(sig)) {
       // Sorry, but the term is not in the input signature!
       notInInputSignature(sig);
     }
   }
 }
 // This method initializes the table with input signatures
 private void initSigTable() {
   sigTable.put(factory.parse("rec-terminate(<logger>,<term>)"), new Boolean(true));
   sigTable.put(factory.parse("rec-monitor(<logger>,<term>)"), new Boolean(true));
 }