%0 Book Section
%A Buscemi, Maria Grazia
%A Montanari, Ugo
%B Proceedings of the 17th European Symposium on Programming (ESOP’08)
%D 2008
%E Drossopoulou, Sophia
%F eprints:120
%I Springer
%P 254-268
%S Lecture Notes in Computer Science
%T Open Bisimulation for the Concurrent Constraint Pi-Calculus
%U http://eprints.imtlucca.it/120/
%V 4960
%X The concurrent constraint pi-calculus (cc-pi-calculus) has been introduced as a model for concluding Service Level Agreements. The cc-pi calculus combines the synchronous communication paradigm of process calculi with the constraint handling mechanism of concurrent constraint programming. While in the original presentation of the calculus a reduction semantics has been proposed, in this work we investigate the abstract semantics of cc-pi processes. First, we define a labelled transition system of the calculus and a notion of open bisimilarity à la pi-calculus that is proved to be a congruence. Next, we give a symbolic characterisation of bisimulation and we prove that the two semantics coincide. Essentially, two processes are open bisimilar if they have the same stores of constraints - this can be statically checked - and if their moves can be mutually simulated. A key idea of the symbolic transition system is to have ‘contextual’ labels, i.e. labels specifying that a process can evolve only in presence of certain constraints. Finally, we show that the polyadic Explicit Fusions calculus introduced by Gardner and Wischik can be translated into monadic cc-pi and that such a transition preserves open bisimilarity. The mapping exploits fusions and tuple unifications as constraints. 
%Z The final publication is available at www.springerlink.com.