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# CCS Dynamic Bisimulation is Progressing

Montanari, U. and Sassone, V. (1991) CCS Dynamic Bisimulation is Progressing. 16th International Symposium on the Mathematical Foundations of Computer Science, MFCS 1991.. pp. 346-356 .

Record type: Conference or Workshop Item (Paper)

## Abstract

Weak Observational Congruence (woc) defined on CCS agents is not a bisimulation since it does not require two states reached by bisimilar computations of woc agents to be still woc, e.g.\ $\alpha.\tau.\beta.nil$ and $\alpha.\beta.nil$ are woc but $\tau.\beta.nil$ and $\beta.nil$ are not. This fact prevents us from characterizing CCS semantics (when $\tau$ 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.

Text
dyn-MFCS91-fin.pdf - Other

Published date: 1991
Venue - Dates: 16th International Symposium on the Mathematical Foundations of Computer Science, MFCS 1991., 1991-01-01
Keywords: dynamic bisimulation, progressing bisimulation, bisimulation congruences, CCS
Organisations: Web & Internet Science

## Identifiers

Local EPrints ID: 261904
URI: https://eprints.soton.ac.uk/id/eprint/261904
ISBN: 3-540-54345-7
PURE UUID: 33fcf44d-65f4-4f29-973a-bbc78c71e567

## Catalogue record

Date deposited: 05 Feb 2006

## Contributors

Author: U. Montanari
Author: V. Sassone

## University divisions

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