Foundations of Software Science and Computational Structures 12th International Conference, FOSSACS 2009, Held as Part of the Joint European Conferences on Theory and Practice of Software, ETAPS 2009, York, UK, March 22-29, 2009, Proceedings

ETAPS 2009 was the 12th instance of the European Joint Conferences on T- oryand Practiceof Software. ETAPS is anannual federatedconference that was establishedin1998bycombininganumberofexistingandnewconferences. This year it comprised ?ve conferences (CC, ESOP, FASE, FOSSACS, TACAS), 22 satellite workshops (ACCAT, ARSPA-WITS, Bytecode, COCV, COMPASS, FESCA, FInCo, FORMED, GaLoP, GT-VMT, HFL, LDTA, MBT, MLQA, OpenCert, PLACES, QAPL, RC, SafeCert, TAASN, TERMGRAPH, and WING),fourtutorials,andseveninvitedlectures(excludingthosethatweres- ci?c to the satellite events). The ?ve main conferences received 532 submissions (including 30 tool demonstration papers), 141 of which were accepted (10 tool demos), giving an overall acceptance rate of about 26%, with most of the c- ferences at around 25%. Congratulations therefore to all the authors who made it to the ?nal programme! I hope that most of the other authors will still have found a way of participating in this exciting event, and that youwill allcontinue submitting to ETAPS and contributing towards making it the best conference on software science and engineering. The events that comprise ETAPS address various aspects of the system - velopment process, including speci?cation, design, implementation, analysis and improvement. The languages, methodologies and tools which support these - tivities are all well within its scope. Di?erent blends of theory and practice are represented, with an inclination towards theory with a practical motivation on the one hand and soundly based practice on the other. Many of the issues involved in software design apply to systems in general, including hardware s- tems, and the emphasis on software is not intended to be exclusive.