The Symposium on Theoretical Aspects of Computer Science (STACS) is - ternately held in France and Germany. The latest conference, February 27 to March 1, 2003 at the Institute of Computer Science, Freie Universit] at Berlin is the twentieth in this series. The previous meetings took place in Paris (1984), Saarbruc ] ken (1985), Orsay (1986), Passau (1987), Bordeaux (1988), Paderborn (1989), Rouen (1990), Hamburg (1991), Cachan (1992), Wurzburg ] (1993), Caen (1994), Munc ] hen (1995), Grenoble (1996), Lub ] eck (1997), Paris (1998), Trier (1999), Lille (2000), Dresden (2001), and...