Scientific Programme (with links to slides and papers, where available) On-line registration Program Committee Luca Aceto (BRICS, Aalborg, DK, co-chair) Wan Fokkink (CWI, NL, co-chair) Rob van Glabbeek (NICTA, AU) Ralf Laemmel (CWI, NL) Peter Mosses (BRICS, Aarhus, DK) David Sands (Chalmers, SE) Alex Simpson (Edinburgh, UK) Simone Tini (Insubria, I) Irek Ulidowski (Leicester, UK, co-chair) Erik de Vink (Eindhoven, NL) Invited speakers Andrew Pitts (Cambridge, UK) Invited tutorial speakers Rob van Glabbeek (NICTA, AU) David Sands (Chalmers, SE) Contact persons Luca Aceto Dept. of CS Aalborg University Fredrik Bajers Vej 7B DK-9220 Aalborg Ø Denmark EMAIL: luca AT cs DOT auc DOT dk Wan Fokkink CWI Department of Software Engineering Kruislaan 413 1098 SJ Amsterdam The Netherlands EMAIL: wan AT cwi DOT nl Irek Ulidowski Department of Computer Science University of Leicester University Road Leicester, LE1 7RH United Kingdom EMAIL: I.Ulidowski AT mcs DOT le DOT ac DOT uk

Aim: Structural operational semantics (SOS) provides a framework for giving operational semantics to programming and specification languages. A growing number of programming languages from commercial and academic spheres have been given usable semantic descriptions by means of structural operational semantics. Because of its intuitive appeal and flexibility, structural operational semantics has found considerable application in the study of the semantics of concurrent processes. Moreover, it is becoming a viable alternative to denotational semantics in the static analysis of programs, and in proving compiler correctness. Recently, structural operational semantics has been successfully applied as a formal tool to establish results that hold for classes of process description languages. This has allowed for the generalization of well-known results in the field of process algebra, and for the development of a meta-theory for process calculi based on the realization that many of the results in this field only depend upon general semantic properties of language constructs. This workshop aims at being a forum for researchers, students and practitioners interested in new developments, and directions for future investigation, in the field of structural operational semantics. One of the specific goals of the workshop is to establish synergies between the concurrency and programming language communities working on the theory and practice of SOS. Moreover, it aims at widening the knowledge of SOS among postgraduate students and young researchers from the U.K. and abroad. In order to achieve this aim, the workshop will have several internationally leading scientists giving invited lectures and tutorials. The invited tutorials and, to some extent, the invited lectures will target postgraduate students specifically, and will provide the training in the SOS methodology as well as stimulating interest in SOS research. The workshop will also mark the publication of a special issue of the Journal of Logic and Algebraic Programming devoted to SOS. Together with original research papers on SOS, this special issue features a definitive version of Gordon Plotkin's 1981 DAIMI memo on SOS, together with a piece by Plotkin on the origins of SOS. All registered workshop participants will receive a copy of this special issue, courtesy of Elsevier. Specific topics of interest include (but are not limited to): programming languages process algebras higher-order formalisms rule formats for operational specifications meaning of operational specifications comparisons between denotational, axiomatic and SOS compositionality of modal logics with respect to operational specifications congruence with respect to behavioural equivalences conservative extensions derivation of proof rules from operational specifications software tools that automate, or are based on, SOS. Papers reporting on applications of SOS to software engineering and other areas of computer science are welcome. Paper submission: We solicit unpublished papers reporting on original research on the general theme of SOS. Prospective authors are invited to submit a pdf or postscript file with their extended abstract, whose length should not exceed 15 pages, by email to all of the co-chairs at their respective email addresses. The email message with the submission should also include, in plain text, contact information for the author(s), together with the title and abstract of the submission. Submissions are to be received by Sunday, 6 June, 2004 . Authors will be notified of acceptance by Wednesday 30 June 2004. Submissions from the PC members are allowed. Proceedings: Preliminary proceedings containing the abstracts of the talks have been published as volume NS-04-1 in the BRICS Notes Series, and will be available at the meeting. The final proceedings of the workshop will appear as a volume in the ENTCS series. If the quality and quantity of the submissions warrant it, the co-chairs plan to arrange a special issue of an archival journal devoted to full versions of selected papers from the workshop. Important Dates: Submission: Sunday 6 June 2004 Notification: Wednesday 30 June 2004 Final version: Friday July 16 2004 Workshop: Monday 30 August 2004.

Sponsorship and Procedure for Grant Applications: We thank BRICS for supporting this event. The workshop is also partly sponsored by the Engineering and Physical Sciences Research Council (EPSRC). Thanks to this support, there are about 15 grants available to U.K-based PhD students to attend the SOS workshop. A typical grant will cover the costs of travel and subsistence, and in special cases the accommodation for one night in London. Note that the workshop registration fee cannot be covered by the grant.

As the number of grants is limited to fifteen, they will be awarded to the eligible students on a "first come first served" basis.

If you are a PhD student researching at a U.K.-based academic institution, you can apply for a grant by emailing Irek Ulidowski (iu3 AT mcs.le.ac.uk) the following information:

1. Full Name
2. Affiliation
3. Topic of Research
4. Supervisor's Details
5. Estimate of Cost of Travel and Accommodation (if really necessary)
6. Short Statement on How the SOS Workshop Will Benefit Your Present and Future Research

Please, copy your email to Luca Aceto (luca AT cs.auc.dk) and Wan Fokkink (wan AT cwi.nl)