bool isIncluded (Lista l1, Lista l2){
  if (l2 == NULL)
    return true;
  else{
    Lista aux1;
    Lista aux2;
    while (l1 != NULL && aux2 != NULL && aux1 != NULL){
      while (l1 != NULL && (*l1).elem != (*l2).elem)
        l1 = (*l1).sig;
      if (l1 != NULL){
        aux1 = (*l1).sig;
        aux2 = (*l2).sig;
        while (aux1 != NULL && aux2 != NULL && (*aux1).elem == (*aux2).elem){
          aux1 = (*aux1).sig;
          aux2 = (*aux2).sig;
        }
        l1 = (*l1).sig;
      }  
    }//primer while
    if (aux2 == NULL)
      return true;
    else
      return false;
  
  }//cierro el else
}//procedimiento