Results 1  10
of
22
Modal and Temporal Logics for Processes
, 1996
"... this paper have been presented at the 4th European Summer School in Logic, Language and Information, University of Essex, 1992; at the Tempus Summer School for Algebraic and Categorical Methods in Computer Science, Masaryk University, Brno, 1993; and the Summer School in Logic Methods in Concurrency ..."
Abstract

Cited by 91 (2 self)
 Add to MetaCart
(Show Context)
this paper have been presented at the 4th European Summer School in Logic, Language and Information, University of Essex, 1992; at the Tempus Summer School for Algebraic and Categorical Methods in Computer Science, Masaryk University, Brno, 1993; and the Summer School in Logic Methods in Concurrency, Aarhus University, 1993. I would like to thank the organisers and the participants of these summer schools, and of the Banff higher order workshop. I would also like to thank Julian Bradfield for use of his Tex tree constructor for building derivation trees and Carron Kirkwood, Faron Moller, Perdita Stevens and David Walker for comments on earlier drafts.
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 ..."
Abstract

Cited by 49 (16 self)
 Add to MetaCart
(Show Context)
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 ..."
Abstract

Cited by 47 (10 self)
 Add to MetaCart
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.
Undecidable Equivalences for Basic Parallel Processes
 13th Conference on Foundations of Software Technology and Theoretical Computer Science
, 1993
"... . Recent results show that strong bisimilarity is decidable for the class of Basic Parallel Processes (BPP), which corresponds to the subset of CCS definable using recursion, action prefixing, nondeterminism and the full merge operator. In this paper we examine all other equivalences in the linear/b ..."
Abstract

Cited by 31 (1 self)
 Add to MetaCart
(Show Context)
. Recent results show that strong bisimilarity is decidable for the class of Basic Parallel Processes (BPP), which corresponds to the subset of CCS definable using recursion, action prefixing, nondeterminism and the full merge operator. In this paper we examine all other equivalences in the linear/branching time hierarchy [12] and show that none of them are decidable for BPP. 1 Introduction Much attention has been devoted to the study of process calculi and in particular to behavioural semantics for these calculi. In order to capture the behavioural aspects of processes, a variety of equivalences have been proposed. Various criteria exist for comparing the merits and deficiencies of these equivalences. A systematic approach consists of classifying the equivalences according to their coarseness. For this purpose van Glabbeek proposed the linear/branching time spectrum which is illustrated in Figure 1 [12]. The least discriminating equivalences are at the bottom of the diagram. Arrows i...
Regularity is Decidable for Normed PA Processes in Polynomial Time
, 1996
"... A process # is regular if it is bisimilar to a process # # with finitely many states. We prove that regularity of normed PA processes is decidable and we present a practically usable polynomialtime algorithm. Moreover, if the tested normed PA process # is regular then the process # # can be ..."
Abstract

Cited by 21 (3 self)
 Add to MetaCart
A process # is regular if it is bisimilar to a process # # with finitely many states. We prove that regularity of normed PA processes is decidable and we present a practically usable polynomialtime algorithm. Moreover, if the tested normed PA process # is regular then the process # # can be e#ectively constructed. It implies decidability of bisimulation equivalence for any pair of processes such that one process of this pair is a normed PA process and the other process has finitely many states.
Simulation preorder over simple process algebras
 Information and Computation
"... We consider the problem of simulation preorder/equivalence between infinitestate processes and finitestate ones. First, we describe a general method how to utilize the decidability of bisimulation problems to solve (certain instances of) the corresponding simulation problems. For certain process c ..."
Abstract

Cited by 13 (5 self)
 Add to MetaCart
(Show Context)
We consider the problem of simulation preorder/equivalence between infinitestate processes and finitestate ones. First, we describe a general method how to utilize the decidability of bisimulation problems to solve (certain instances of) the corresponding simulation problems. For certain process classes, the method allows to design effective reductions of simulation problems to their bisimulation counterparts and some new decidability results for simulation have already been obtained in this way. Then we establish the decidability border for the problem of simulation preorder/equivalence between infinitestate processes and finitestate ones w.r.t. the hierarchy of process rewrite systems. In particular, we show that simulation preorder (in both directions) and simulation equivalence are decidable in EXPTIME between pushdown processes and finitestate ones. On the other hand, simulation preorder is undecidable between PA and finitestate processes in both directions. These results also hold for those PA and finitestate processes which are deterministic and normed, and thus immediately extend to trace preorder. Regularity (finiteness) w.r.t. simulation and trace equivalence is also shown to be undecidable for PA. Finally, we prove that simulation preorder (in both directions) and simulation equivalence are intractable between all classes of infinitestate systems (in the hierarchy of process rewrite systems) and finitestate ones. This result is obtained by showing that the problem whether a BPA (or BPP) process simulates a finitestate one is PSPACEhard, and the other direction is coNPhard; consequently, simulation equivalence between BPA (or BPP) and finitestate processes is also coNPhard. 1
Simulation Preorder on Simple Process Algebras
, 1999
"... We consider the problem of simulation preorder/equivalence between infinitestate processes and finitestate ones. We prove that simulation preorder (in both directions) and simulation equivalence are intractable between all major classes of infinitestate systems and finitestate ones. This resul ..."
Abstract

Cited by 10 (4 self)
 Add to MetaCart
We consider the problem of simulation preorder/equivalence between infinitestate processes and finitestate ones. We prove that simulation preorder (in both directions) and simulation equivalence are intractable between all major classes of infinitestate systems and finitestate ones. This result is obtained by showing that the problem whether a BPA (or BPP) process simulates a finitestate one is PSPACEhard, and the other direction is coNPhard; consequently, simulation equivalence between BPA (or BPP) and finitestate processes is also coNPhard. The decidability border for the mentioned problem is also established. Simulation preorder (in both directions) and simulation equivalence are shown to be decidable in EXPTIME between pushdown processes and finitestate ones. On the other hand, simulation preorder is undecidable between PA and finitestate processes in both directions. The obtained results also hold for those PA and finitestate processes which are determini...
Decidability Issues for InfiniteState Processes  a Survey
, 1996
"... ... In this paper we survey recent developments and current trends within a new field of study within process algebra, namely that of decidability issues for processes with infinite transition graphs. ..."
Abstract

Cited by 9 (0 self)
 Add to MetaCart
... In this paper we survey recent developments and current trends within a new field of study within process algebra, namely that of decidability issues for processes with infinite transition graphs.
Weak bisimilarity with infinitestate systems can be decided in polynomial time
 In Proc. of CONCUR'99, volume 1664 of LNCS
, 1999
"... Abstract. We prove that weak bisimilarity is decidable in polynomial time between BPA and finitestate processes, and between normed BPP and finitestate processes. To the best of our knowledge, these are the first polynomial algorithms for weak bisimilarity with infinitestate systems. 1 ..."
Abstract

Cited by 8 (5 self)
 Add to MetaCart
(Show Context)
Abstract. We prove that weak bisimilarity is decidable in polynomial time between BPA and finitestate processes, and between normed BPP and finitestate processes. To the best of our knowledge, these are the first polynomial algorithms for weak bisimilarity with infinitestate systems. 1
Comparing expressibility of normed BPA and normed BPP processes
 Acta Informatica
, 1999
"... Summary. We present an exact characterization of those transition systems which can be equivalently (up to bisimilarity) defined by the syntax of normed BPAτ and normed BPPτ processes. We give such a characterization for the subclasses of normed BPA and normed BPP processes as well. Next we demonstr ..."
Abstract

Cited by 6 (4 self)
 Add to MetaCart
(Show Context)
Summary. We present an exact characterization of those transition systems which can be equivalently (up to bisimilarity) defined by the syntax of normed BPAτ and normed BPPτ processes. We give such a characterization for the subclasses of normed BPA and normed BPP processes as well. Next we demonstrate the decidability of the problem whether for a given normed BPAτ process ∆ there is some unspecified normed BPPτ process ∆ ′ such that ∆ and ∆ ′ are bisimilar. The algorithm is polynomial. Furthermore, we show that if the answer to the previous question is positive, then (an example of) the process ∆ ′ is effectively constructible. Analogous algorithms are provided for normed BPPτ processes. Simplified versions of the mentioned algorithms which work for normed BPA and normed BPP are given too. As a simple consequence we obtain the decidability of bisimilarity in the union of normed BPAτ and normed BPPτ processes. 1