SELECT ?s ?sf ?sl
WHERE {
      ?s a divont:Periodo . ?l a divont:Line .
      ?s divont:First_symbol ?sf . ?l divont:First_symbol ?lf .
      ?s divont:Last_symbol ?sl . ?l divont:Last_symbol ?ll .
      FILTER (!function:Precedes(?sf,?lf)) .
      FILTER (!function:Precedes(?ll, ?sl)) .
};