This volume gives the proceedings of the ninth Symposium on
Theoretical Aspects of Computer Science (STACS). This
annual symposium is held alternately in France and Germany
and is organized jointly by the Special Interest Group for
Fundamental Computer Science of the Association Francaise
des Sciences et Technologies de l'Information et des
Syst mes (AFCET) and the Special Interest Group for
Theoretical Computer Science of the Gesellschaft f}r
Informatik (GI).
The volume includes three invited lectures and sections on
parallel algorithms, logic and semantics, computational
geometry, automata and languages, structural complexity,
computational geometry and learning theory, complexity and
communication, distributed systems, complexity, algorithms,
cryptography, VLSI, words and rewriting, and systems.