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Author van Glabbeek, Rob J. ♦ Weijland, W. Peter
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
File Format PDF
Copyright Year ©1996
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Abstraction ♦ Action refinement ♦ Bisimulation ♦ Branching time ♦ Concurrency ♦ Process algebra semantic equivalence
Abstract In comparative concurrency semantics, one usually distinguishes between linear time and branching time semantic equivalences. Milner's notion of observatin equivalence is often mentioned as the standard example of a branching time equivalence. In this paper we investigate whether observation equivalence really does respect the branching structure of processes, and find that in the presence of the unobservable action τ of CCS this is not the case.Therefore, the notion of branching bisimulation equivalence is introduced which strongly preserves the branching structure of processes, in the sense that it preserves computations together with the potentials in all intermediate states that are passed through, even if silent moves are involved. On closed CCS-terms branching bisimulation congruence can be completely axiomatized by the single axion scheme: $\textit{a.(τ.(y+z)+y)=a.(y+z)}$ (where $\textit{a}$ ranges over all actions) and the usual loaws for strong congruence.We also establish that for sequential processes observation equivalence is not preserved under refinement of actions, whereas branching bisimulation is.For a large class of processes, it turns out that branching bisimulation and observation equivalence are the same. As far as we know, all protocols that have been verified in the setting of observation equivalence happen to fit in this class, and hence are also valid in the stronger setting of branching bisimulation equivalence.
ISSN 00045411
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 1996-05-01
Publisher Place New York
e-ISSN 1557735X
Journal Journal of the ACM (JACM)
Volume Number 43
Issue Number 3
Page Count 46
Starting Page 555
Ending Page 600


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Source: ACM Digital Library