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37
Deciding BisimulationLike Equivalences with FiniteState Processes
, 1999
"... We show that characteristic formulae for nitestate systems up to bisimulationlike equivalences (e.g., strong and weak bisimilarity) can be given in the simple branchingtime temporal logic EF. Since EF is a very weak fragment of the modal µcalculus, model checking with EF is decidable for many mo ..."
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Cited by 49 (16 self)
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We show that characteristic formulae for nitestate systems up to bisimulationlike equivalences (e.g., strong and weak bisimilarity) can be given in the simple branchingtime temporal logic EF. Since EF is a very weak fragment of the modal µcalculus, model checking with EF is decidable for many more classes of infinitestate systems. This yields a general method for proving decidability of bisimulationlike equivalences between infinitestate processes and finitestate ones. We apply this method to the class of PAD processes, which strictly subsumes PA and pushdown (PDA) processes, showing that a large class of bisimulationlike equivalences (including, e.g., strong and weak bisimilarity) is decidable between PAD and finitestate processes. On the other hand, we also demonstrate that no `reasonable' bisimulationlike equivalence is decidable between stateextended PA processes and finitestate ones. Furthermore, weak bisimilarity with finitestate processes is shown to be undecidable even for state...
Actions Speak Louder than Words: Proving Bisimilarity for ContextFree Processes
, 1997
"... Baeten, Bergstra, and Klop (and later Caucal) have proved the remarkable result that bisimulation equivalence is decidable for irredundant contextfree grammars. In this paper we provide a much simpler and much more direct proof of this result using a tableau decision method involving goaldirected ..."
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Cited by 47 (10 self)
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Baeten, Bergstra, and Klop (and later Caucal) have proved the remarkable result that bisimulation equivalence is decidable for irredundant contextfree grammars. In this paper we provide a much simpler and much more direct proof of this result using a tableau decision method involving goaldirected rules. The decision procedure also provides the essential part of the bisimulation relation between two processes which underlies their equivalence. We also show how to obtain a sound and complete sequentbased equational theory for such processes from the tableau system and how one can extract what Caucal calls a fundamental relation from a successful tableau.
Automated Compositional Markov Chain Generation for a PlainOld Telephone System
 SCIENCE OF COMPUTER PROGRAMMING
, 1999
"... Obtaining performance models, like Markov chains and queueing networks, for systems of significant complexity and magnitude is a di#cult task that is usually tackled using human intelligence and experience. This holds in particular for performance models of a highly irregular nature. In this paper w ..."
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Cited by 45 (25 self)
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Obtaining performance models, like Markov chains and queueing networks, for systems of significant complexity and magnitude is a di#cult task that is usually tackled using human intelligence and experience. This holds in particular for performance models of a highly irregular nature. In this paper we argue by means of a nontrivial example  a plainold telephone system (POTS)  that a stochastic extension of process algebra can diminish these problems by permitting an automatic generation of Markov chains. We introduce a stochastic process algebra that separates the advance of time and action occurrences. For the sake of specification convenience we incorporate an elapse operator that allows the modular description of time constraints where delays are described by continuous phasetype distributions. Using this language we provide a formal specification of the POTS and show how a stochastic process of more than 10 7 states is automatically obtained from this system description. ...
Argos: an automatonbased synchronous language
, 2001
"... Argos belongs to the family of synchronous languages, designed for programming reactive systems: (Lustre ..."
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Cited by 39 (8 self)
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Argos belongs to the family of synchronous languages, designed for programming reactive systems: (Lustre
Rooted branching bisimulation as a congruence
 Journal of Computer and System Sciences
, 2000
"... This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, an ..."
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Cited by 17 (6 self)
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This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, and negative premises. 1
Modal Model Theory
 ANNALS OF PURE AND APPLIED LOGIC
, 1995
"... This paper contributes to the model theory of modal logic using bisimulations as the fundamental tool. A uniform presentation is given of modal analogues of wellknown definability and preservation results from firstorder logic. These results include algebraic characterizations of modal equivalen ..."
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Cited by 15 (6 self)
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This paper contributes to the model theory of modal logic using bisimulations as the fundamental tool. A uniform presentation is given of modal analogues of wellknown definability and preservation results from firstorder logic. These results include algebraic characterizations of modal equivalence, and of the modally definable classes of models; the preservation results concern preservation of modal formulas under submodels, unions of chains, and homomorphisms.
A Process Algebra with Distributed Priorities
 Theoretical Computer Science
, 1996
"... . This paper presents a process algebra for distributed systems in which some actions may take precedence over others. In contrast with existing approaches to priorities, our algebra only allows actions to preempt others at the same #location" and therefore captures a notion of localizedpreced ..."
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Cited by 14 (3 self)
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. This paper presents a process algebra for distributed systems in which some actions may take precedence over others. In contrast with existing approaches to priorities, our algebra only allows actions to preempt others at the same #location" and therefore captures a notion of localizedprecedence. Using Park's and Milner's notion of strong bisimulation as a basis, we develop a behavioral congruence and axiomatize it for #nite processes; we also derive an associated observational congruence. Simple examples highlight the utility of the theory. 1 Introduction Process algebras #11, 13# provide widely studied frameworks for modeling and verifying concurrent systems #9#. Such theories typically consist of a simple language with a wellde#ned operational semantics given in terms of labeled transition systems; a behavioral equivalence is then used to relate implementations and speci#cations, which are both given as terms in the language. In order to facilitate compositional reasoning, in wh...
A Complete Equational Axiomatization for MPA with String Iteration
 DEPARTMENT OF MATHEMATICS AND COMPUTER SCIENCE, AALBORG UNIVERSITY
, 1995
"... We study equational axiomatizations of bisimulation equivalence for the language obtained by extending Milner's basic CCS with string iteration. String iteration is a variation on the original binary version of the Kleene star operation p*q obtained by restricting the first argument to be a ..."
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Cited by 14 (5 self)
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We study equational axiomatizations of bisimulation equivalence for the language obtained by extending Milner's basic CCS with string iteration. String iteration is a variation on the original binary version of the Kleene star operation p*q obtained by restricting the first argument to be a nonempty sequence of atomic actions. We show that, for every positive integer k, bisimulation equivalence over the set of processes in this language with loops of length at most k is finitely axiomatizable. We also offer a countably infinite equational theory that completely axiomatizes bisimulation equivalence over the whole language. We prove that this result cannot be improved upon by showing that no finite equational axiomatization of bisimulation equivalence over basic CCS with string iteration can exist, unless the set of actions is empty.
A Schemabased Approach to Modeling and Querying WWW Data
 In Proc. of FQAS'98
, 1998
"... . The steady growth of the amount of data published on the World Wide Web has led to a number of attempts to provide effective Web querying, as a complement to conventional navigation techniques. In this paper, we propose to support WWW querying by specifying both logical and navigational aspects of ..."
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Cited by 10 (9 self)
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. The steady growth of the amount of data published on the World Wide Web has led to a number of attempts to provide effective Web querying, as a complement to conventional navigation techniques. In this paper, we propose to support WWW querying by specifying both logical and navigational aspects of a Web site through the unifying notion of schema. Schemata are a powerful tool for classifying and maintaining WWW data as well as for semanticsaware search on the Web. Moreover, schema availability is the basis for an effective flexible querying mechanism. Following the style of such languages as Good and GLog, the WGLog language described in the paper uniformly represents site schemata, instances and queries as graphs. Gracefully supporting schemata that are huge or subject to change, WGLog adequately represents data whose structure is less rigid than that of traditional databases; moreover, it allows for a uniform representation of flexible queries and views, the latter expressing cu...
On the Completeness of the Equations for the Kleene Star in bisimulation
"... A classical result from Redko [14] says that there does not exist a complete finite equational axiomatization for the Kleene star modulo trace equivalence. Fokkink and Zantema [9] showed that there does exist a complete finite equational axiomatization for the Kleene star up to strong bisimulation e ..."
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Cited by 9 (3 self)
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A classical result from Redko [14] says that there does not exist a complete finite equational axiomatization for the Kleene star modulo trace equivalence. Fokkink and Zantema [9] showed that there does exist a complete finite equational axiomatization for the Kleene star up to strong bisimulation equivalence. Their proof is based on a sophisticated term rewriting analysis. In this paper, we present amuch simpler and shorter completeness proof. Furthermore, we show that the three equations for the Kleene star are all essential for this completeness result.