Abstract
Weak Observational Congruence (woc) defined on CCS agents is not a bisimulation since it does not reguire two states reached by bisimilar computations of woc agents to be still woc, e.g. α.τ.β.nil and α.β.nil are woc but τ.β.nil and β.nil are not. This fact prevents us from characterizing CCS semantics (when τ is considered invisible) as a final algebra, since the semantic function would induce an equivalence over the agents that is both a congruence and a bisimulation.
In the paper we introduce a new behavioural equivalence for CCS agents, which is the coarsest among those bisimulations which are also congruences. We call it Dynamic Observational Congruence because it expresses a natural notion of equivalence for concurrent systems required to simulate each other in the presence of dynamic, i.e. run time, (re)configurations. We provide an algebraic characterization of Dynamic Congruence in terms of a universal property of finality.
Furthermore we introduce Progressing Bisimulation, which forces processes to simulate each other performing explicit steps. We provide an algebraic characterization of it in terms of finality, two characterizations via modal logic in the style of HML, and a complete axiomatization for finite agents. Finally, we prove that Dynamic Congruence and Progressing Bisimulation coincide for CCS agents. Thus the title of the paper.
Research supported in part by HEWLETT-PACKARD Laboratories, Pisa Science Center.
Preview
Unable to display preview. Download preview PDF.
References
S. Abramsky. A Domain Equation for Bisimulation, Technical report, Department of Computing, Imperial College, London, 1988.
P. Aczel. Non-Well-Founded Sets. CSLI Lecture Notes n. 14, Stanford University, 1987.
D. Benson and O. Ben-Shachar. Bisimulations of Automata. Information and Computation, n. 79, 1988.
P. Degano, R. De Nicola, and U. Montanari. A Partial Ordering Semantics for CCS. Theoretical Computer Science, n. 75, 1990.
R. De Nicola. Extensional Equivalence for Transition Systems. Acta Informatica, n. 24, 1987.
G. Ferrari and U. Montanari. Towards the Unification of Models for Concurrency. In Proceedings of CAAP '90. LNCS n. 431, Springer Verlag, 1990.
G. Ferrari, U. Montanari, and M. Mowbray. On Causality Observed Incrementally, Finally. In Proceedings of TAPSOFT '91. LNCS n. 493, Springer Verlag, 1991.
U. Goltz and R. van Glabbeek. Equivalence Notions for Concurrent System and Refinement of Actions. In Proceedings of MFCS '89. LNCS n. 379, Springer Verlag, 1989.
R. Keller. Formal Verification of Paralle Programs. Communications of the ACM, vol. 7, 1976.
R. Milner. A Calculus of Communicating Systems. Lecture Notes in Computer Science, n. 92. Springer Verlag, 1980.
R. Milner. Concurrency and Communication. Prentice Hall, 1989.
U. Montanari and V. Sassone. Dynamic Bisimulation. Technical Report TR 13/90, Dipartimento di Informatica, Università di Pisa, 1990.
U. Montanari and M. Sgamma. Canonical Representatives for Observational Equivalences Classes. In Proceedings of Colloquium on the Resolution of Equations in Algebraic Structures. North Holland, 1989.
V. Manca, A. Salibra, and G. Scollo. Equational Type Logic. Theoretical Computer Science, n. 77, 1990.
M. Nielsen, G. Plotkin, and G. Winskel. Petri Nets, Event Structures and Domains, Part 1. Theoretical Computer Science, n. 13, 1981.
D. Park. Concurrency and Automata on Infinite Sequences. In Proceedings of GI. LNCS n. 104, Springer Verlag, 1981.
C.A. Petri. Kommunikation mit Automaten. PhD thesis, Institut für Instrumentelle Mathematik, Bonn, FRG, 1962.
G. Plotkin. A Structured Approach to Operational Semantics. DAIMI FN-19, Computer Science Dept., Aarhus University, 1981.
V. Pratt. Modelling Concurrency with Partial Orders. International Journal of Parallel Programming, n. 15, 1986.
R. van Glabbeek. Bounded Nondeterminism and the Approximation Induction Principle in Process Algebra. In Proceedings of STACS 87. LNCS n. 247, Springer Verlag, 1987.
R. van Glabbeek and W. Weijland. Branching Time and Abstraction in Bisimulation Semantics. In Proceedings of IFIP 11th World Computer Congress, August 1989.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1991 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Montanari, U., Sassone, V. (1991). CCS dynamic bisimulation is progressing. In: Tarlecki, A. (eds) Mathematical Foundations of Computer Science 1991. MFCS 1991. Lecture Notes in Computer Science, vol 520. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-54345-7_78
Download citation
DOI: https://doi.org/10.1007/3-540-54345-7_78
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-54345-9
Online ISBN: 978-3-540-47579-8
eBook Packages: Springer Book Archive