The present volume contains the proceedings of the international conference Foundations of
Software Science and Computation Structures(FOSSACS)2003 held in Warsaw Poland April 7 9
2003. FOSSACS is an event of the Joint European Conferences on Theory and Practice of Software
(ETAPS). The pre- ous ?ve FOSSACS conferences took place in Lisbon (1998) Amsterdam (1999)
Berlin (2000) Genoa (2001) and Grenoble (2002). FOSSACS presents original papers on
foundational researchwith a clear s-
ni?cancetosoftwarescience.TheProgramCommitteeinvitedpapersontheories and methodsto supportthe
analysis integration synthesis transformation and veri?cation of programs and software systems.
We identi?ed the following t- ics in particular: algebraic models automata and language
theory behavioural equivalences categorical models computation processes over discrete and
c- tinuous data computation structures logics of programs modal spatial and temporallogics
modelsof concurrent reactive distributed and mobile systems processalgebrasandcalculi
semanticsofprogramminglanguages softwaresp- i?cation and re?nement transition systems and
type systems and type theory. We received 96 submissions of which 2 were withdrawn. This
proceedings consists of 27 papers. The ?rst A Game Semantics for Generic Polymorphism
accompanies the invited lecture by Samson Abramsky University of Oxford. The remaining 26 were
selected for publication by the Program Committee during a week-long electronic discussion. I
sincerely thank all the authors of papers submitted to FOSSACS 2003 the number and the quality
of papers were exceptionally high this year. Moreover I would like to thank all the members of
the ProgramCommittee for the excellent job they did during a rather demanding selection process
and to thank all our subreferees for their invaluable contributions to this process.
