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Refinement of Actions and Equivalence Notions for Concurrent Systems
 Acta Informatica
, 1998
"... This paper combines and extends the material of [GGa/c/d/e], except for the part in [GGc] on refinement of transitions in Petri nets and the discussion of TCSPlike parallel composition in [GGe]. An informal presentation of some basic ingredients of this paper appeared as [GGb]. Among others, th ..."
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Cited by 59 (3 self)
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This paper combines and extends the material of [GGa/c/d/e], except for the part in [GGc] on refinement of transitions in Petri nets and the discussion of TCSPlike parallel composition in [GGe]. An informal presentation of some basic ingredients of this paper appeared as [GGb]. Among others, the treatment of action refinement in stable and nonstable event structures is new. The research reported here was supported by Esprit project 432 (METEOR), Esprit Basic Research Action 3148 (DEMON), Sonderforschungsbereich 342 of the TU Munchen, ONR grant N0001492J1974 and the Human Capital and Mobility Cooperation Network EXPRESS (Expressiveness of Languages for Concurrency). Contents
The importance of the left merge operator in process algebras
 Proceedings 17 th ICALP
"... Abstract. In this paper, we examine quational a~xiomatisations for PA, the process algebra of Bergstra and Klop, which is a simple subset of their full language ACP. The language PA has two combinators for concurrent execution: theusual full merge operator ~ and the more esoteric left merge operator ..."
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Cited by 35 (0 self)
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Abstract. In this paper, we examine quational a~xiomatisations for PA, the process algebra of Bergstra and Klop, which is a simple subset of their full language ACP. The language PA has two combinators for concurrent execution: theusual full merge operator ~ and the more esoteric left merge operator [. Though this latter combinator is somewhat semantically unusual, we demonstrate its importance by proving that, whereas a finite sound and complete equa ional theory exists for PA, no such finite theory can exist for PA in the absence of the left merge operator. 1
Action Refinement
 Handbook of Proacess Algebra
, 2000
"... S. All local authors can be reached via email at the address lastname@cs.unibo.it. Questions and comments should be addressed to tradmin@cs.unibo.it. Recent Titles from the UBLCS Technical Report Series 974 An Algebra of Actors, M. Gaspari, G. Zavattaro, May 1997. 975 On the Turing Equivalen ..."
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Cited by 29 (4 self)
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S. All local authors can be reached via email at the address lastname@cs.unibo.it. Questions and comments should be addressed to tradmin@cs.unibo.it. Recent Titles from the UBLCS Technical Report Series 974 An Algebra of Actors, M. Gaspari, G. Zavattaro, May 1997. 975 On the Turing Equivalence of Linda Coordination Primitives, N. Busi, R. Gorrieri, G. Zavattaro, May 1997 (Revised October 1998). 976 A Process Algebraic View of Linda Coordination Primitives, N. Busi, R. Gorrieri, G. Zavattaro, May 1997. 977 Validating a Software Architecture with respect to an Architectural Style, P. Ciancarini, W. Penzo, July 1997. 978 System Support for PartitionAware Network Applications, O. Babaoglu, R. Davoli, A. Montresor, R. Segala, October 1997. 979 Generalized SemiMarkovian Process Algebra, M. Bravetti, M. Bernardo, R. Gorrieri, October 1997. 981 Group Communication in Partitionable Systems: Specification and Algorithms, O. Babao glu, R. Davoli, A. Montresor, April 1998. 982...
Concurrent Kleene Algebra
"... A concurrent Kleene algebra offers, next to choice and iteration, operators for sequential and concurrent composition, related by an inequational form of the exchange law. We show applicability of the algebra to a partiallyordered trace model of program execution semantics and demonstrate its usefu ..."
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Cited by 22 (3 self)
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A concurrent Kleene algebra offers, next to choice and iteration, operators for sequential and concurrent composition, related by an inequational form of the exchange law. We show applicability of the algebra to a partiallyordered trace model of program execution semantics and demonstrate its usefulness by validating familiar proof rules for sequential programs (Hoare triples) and for concurrent ones (Jones’s rely/guarantee calculus). This involves an algebraic notion of invariants; for these the exchange inequation strengthens to an equational distributivity law. Most of our reasoning has been checked by computer.
Propositional Temporal Logics and Equivalences
 the Proc. of CONCUR
, 1992
"... We compare propositional temporal logics by comparing the equivalences that they induce on models. Linear time, branching time and partial order temporal logics are considered. The logics are interpreted on occurrence transition systems, generated by labelled prime event structures without autoco ..."
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Cited by 15 (5 self)
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We compare propositional temporal logics by comparing the equivalences that they induce on models. Linear time, branching time and partial order temporal logics are considered. The logics are interpreted on occurrence transition systems, generated by labelled prime event structures without autoconcurrency. The induced equivalences are also compared to directly defined equivalences, e.g., history preserving bisimulation, pomset bisimulation, pomset trace equivalence, and others. It is then shown which of the induced equivalences are and which are not preserved under action refinement. Rather unexpectedly, the addition of the backward next step operator to the weakest logic considered yields a logic stronger than all others. It is shown that weak history preserving bisimulation can be obtained as the equivalence induced by a slightly constrained version of that logic. 1 Introduction Currently a lot of formalisms to describe concurrent computations exist. Even only regarding ...
A logic with reverse modalities for historypreserving bisimulations
 In Proceedings 18th International Workshop on Expressiveness in Concurrency, volume 64 of EPTCS
, 2011
"... We introduce event identifier logic (EIL) which extends HennessyMilner logic by the addition of (1) reverse as well as forward modalities, and (2) identifiers to keep track of events. We show that this logic corresponds to hereditary historypreserving (HH) bisimulation equivalence within a particu ..."
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Cited by 6 (1 self)
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We introduce event identifier logic (EIL) which extends HennessyMilner logic by the addition of (1) reverse as well as forward modalities, and (2) identifiers to keep track of events. We show that this logic corresponds to hereditary historypreserving (HH) bisimulation equivalence within a particular trueconcurrency model, namely stable configuration structures. We furthermore show how natural sublogics of EIL correspond to coarser equivalences. In particular we provide logical characterisations of weak historypreserving (WH) and historypreserving (H) bisimulation. Logics corresponding to HH and H bisimulation have been given previously, but not to WH bisimulation (when autoconcurrency is allowed), as far as we are aware. We also present characteristic formulas which characterise individual structures with respect to historypreserving equivalences. 1
A Semantics for Multiprocessor Systems
 In European Symposium On Programming (ESOP): LNCS 582
, 1991
"... In this paper we presentamultiprocessor semantics for CCS #Mil80#. An operational semantics for processes under a #nite number of processors is developed. The e#ect of adding or removing processors from the system is studied. A notion of strong bisimulation induced by the new semantics is de#ned. ..."
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Cited by 2 (1 self)
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In this paper we presentamultiprocessor semantics for CCS #Mil80#. An operational semantics for processes under a #nite number of processors is developed. The e#ect of adding or removing processors from the system is studied. A notion of strong bisimulation induced by the new semantics is de#ned. Issues related to a complete axiomatization of this congruence are examined and a complete equational system for a subset of CCS is presented. 1 Introduction The idea of using observations or labeled transition systems as the basis for describing behaviors for concurrent systems is well known. However, most of the initial work for concurrent systems resulted in an `interleaving semantics'. That is, parallelism was not distinguishable from nondeterminism. Work by #DDM88# uses the notion of causality to present a noninterleaving semantics for CCS. #CH89# develop a theory based on the spatial distribution of processes. #KHCB91# uses the notion of location to develop a theory which accoun...
A Hierarchy of Reverse Bisimulations on Stable Configuration Structures
 UNDER CONSIDERATION FOR PUBLICATION IN MATH. STRUCT. IN COMP. SCIENCE
, 2010
"... The relationships between various equivalences on stable configuration structures, including interleaving bisimulation (IB), step bisimulation (SB), pomset bisimulation and hereditary historypreserving (HH) bisimulation, have been investigated by van Glabbeek and Goltz (and later Fecher). Since H ..."
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Cited by 2 (1 self)
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The relationships between various equivalences on stable configuration structures, including interleaving bisimulation (IB), step bisimulation (SB), pomset bisimulation and hereditary historypreserving (HH) bisimulation, have been investigated by van Glabbeek and Goltz (and later Fecher). Since HH bisimulation may be characterised by the use of reverse as well as forward transitions, it is of interest to investigate these and other forms of bisimulations where both forward and reverse transitions are allowed. Bednarczyk asked whether SB with reverse steps is as strong as HH bisimulation. We answer this question negatively. We give various characterisations of SB with reverse steps, showing that forward steps do not add power. We strengthen Bednarczyk’s result that, in the absence of autoconcurrency, reverse IB is as strong as HH bisimulation, by showing that we need only exclude autoconcurrent events at the same depth in the configuration. We consider several other forms of observations of reversible behaviour. We define a wide range of bisimulations by mixing the forward and reverse observations. We investigate the power of these bisimulations and represent the relationships between them as a hierarchy which has IB at the bottom and HH at the top.