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13
Focus points and convergent process operators: A proof strategy for protocol veri cation
, 1995
"... We present a strategy for nding algebraic correctness proofs for communication systems. It is described in the setting of CRL [11], which is, roughly, ACP [2, 3] extended with a formal treatment of the interaction between data and processes. The strategy has already been applied successfully in [4] ..."
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Cited by 39 (11 self)
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We present a strategy for nding algebraic correctness proofs for communication systems. It is described in the setting of CRL [11], which is, roughly, ACP [2, 3] extended with a formal treatment of the interaction between data and processes. The strategy has already been applied successfully in [4] and [10], but was not explicitly identi ed as such. Moreover, the protocols that were veri ed in these papers were rather complex, so that the general picture was obscured by the amount of details. In this paper, the proof strategy is materialised in the form of de nitions and theorems. These results reduce a large part of protocol veri cation to a number of trivial facts concerning data parameters occurring in implementation and speci cation. This greatly simpli es protocol veri cations and makes our approach amenable to mechanical assistance � experiments in this direction seem promising. The strategy is illustrated by several small examples and one larger example, the Concurrent Alternating Bit Protocol (CABP). Although simple, this protocol contains a large amount ofinternal parallelism, so that all relevant issuesmaketheir appearance.
Verification of Temporal Properties of Processes in a Setting with Data
 In A.M. Haeberer, editor, AMAST’98, volume 1548 of LNCS
, 1999
"... . We define a valuebased modal calculus, built from firstorder formulas, modalities, and fixed point operators parameterized by data variables, which allows to express temporal properties involving data. We interpret this logic over Crl terms defined by linear process equations. The satisfacti ..."
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Cited by 22 (8 self)
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. We define a valuebased modal calculus, built from firstorder formulas, modalities, and fixed point operators parameterized by data variables, which allows to express temporal properties involving data. We interpret this logic over Crl terms defined by linear process equations. The satisfaction of a temporal formula by a Crl term is translated to the satisfaction of a firstorder formula containing parameterized fixed point operators. We provide proof rules for these fixed point operators and show their applicability on various examples. 1 Introduction In recent years we have applied process algebra in numerous settings [4, 8, 12]. The first lesson we learned is that process algebra pur sang is not very handy, and we need an extension with data. This led to the language Crl (micro Common Representation Language) [13]. The next observation was that it is very convenient to eliminate the parallel operator from a process description and reduce it to a very restricted form, whi...
Specification of Rewriting Strategies
 2nd International Workshop on the Theory and Practice of Algebraic Specifications (ASF+SDF'97), Electronic Workshops in Computing
, 1997
"... Userdefinable strategies for the application of rewrite rules provide a means to construct transformation systems that apply rewrite rules in a controlled way. This paper describes a strategy language and its interpretation. The language is used to control the rewriting of terms using labeled rewri ..."
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Cited by 16 (5 self)
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Userdefinable strategies for the application of rewrite rules provide a means to construct transformation systems that apply rewrite rules in a controlled way. This paper describes a strategy language and its interpretation. The language is used to control the rewriting of terms using labeled rewrite rules. Rule labels are atomic strategies. Compound strategies are formed by means of sequential composition, nondeterministic choice, left choice, fixed point recursion, and two primitives for expressing term traversal. Several complex strategies such as bottomup and topdown application and (parallel) innermost and (parallel) outermost reduction can be defined in terms of these primitives. The paper contains two case studies of the application of strategies. 1 Introduction Term rewriting is an ideal technique for program transformation where the transformation of one construct into another is defined by means of rewrite rules. Usually, the rewrite engine contracts redexes according to ...
A Note on n Similar Parallel Processes
 ERCIM Workshop on Formal Methods for Industrial Critical Systems
, 1997
"... We show that defining a finite but unbounded number of parallel processes using the equation S(k, dt) = P (0, get(0, dt))/eq(k, 0).(S(k  1, dt)  P (k, get(k, dt))) is well defined, if one adopts the principle CLRSP. We also provide means to easily derive a linear process equation with the same b ..."
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Cited by 5 (3 self)
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We show that defining a finite but unbounded number of parallel processes using the equation S(k, dt) = P (0, get(0, dt))/eq(k, 0).(S(k  1, dt)  P (k, get(k, dt))) is well defined, if one adopts the principle CLRSP. We also provide means to easily derive a linear process equation with the same behaviour as S(k, dt).
A linear processalgebraic format for probabilistic systems with data
"... Abstract—This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises si ..."
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Cited by 2 (2 self)
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Abstract—This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises similar techniques for traditional process algebras with data, and — more importantly — treats data and datadependent probabilistic choice in a fully symbolic manner, paving the way to the symbolic analysis of parameterised probabilistic systems. Keywordsprobabilistic process algebra, linearisation, datadependent probabilistic choice, symbolic transformations I.
A linear processalgebraic format with data for probabilistic automata
, 2011
"... This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises similar te ..."
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Cited by 2 (2 self)
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This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises similar techniques for traditional process algebras with data, and — more importantly — treats data and datadependent probabilistic choice in a fully symbolic manner, leading to the symbolic analysis of parameterised probabilistic systems. We discuss several reduction techniques that can easily be applied to our models. A validation of our approach on two benchmark leader election protocols shows reductions of more than an order of magnitude.
Checking Verifications of Protocols and Distributed Systems By Computer
, 1998
"... We provide a treatise about checking proofs of distributed systems by computer using general purpose proof checkers. In particular, we present two approaches to verifying and checking the verification of the Sequential Line Interface Protocol (SLIP), one using rewriting techniques and one using the ..."
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Cited by 2 (1 self)
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We provide a treatise about checking proofs of distributed systems by computer using general purpose proof checkers. In particular, we present two approaches to verifying and checking the verification of the Sequential Line Interface Protocol (SLIP), one using rewriting techniques and one using the socalled cones and foci theorem. Both verifications are carried out in the setting of process algebra. Finally, we present an overview of literature containing checked proofs. Note: The research of the second author is supported by Human Capital Mobility (HCM). 1 Proof checkers Anyone trying to use a proof checker, e.g. Isabelle [67, 68], HOL [29], Coq [20], PVS [78], BoyerMoore [14] or many others that exist today has experienced the same frustration. It is very difficult to prove even the simplest theorem. In the first place it is difficult to get acquainted to the logical language of the system. Most systems employ higher order logics that are extremely versatile and expressive. Howev...
Specification and Implementation of Components of a muCRL Toolbox
 Utrecht University
, 1995
"... We develop a set of tools to translate linear ¯CRL specifications to finite transition systems. These tools are intended to function as the core of larger toolsets comprising model checkers, weak or branching bisimulation checkers, simulators, etc. The main problem in constructing these larger tools ..."
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Cited by 1 (0 self)
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We develop a set of tools to translate linear ¯CRL specifications to finite transition systems. These tools are intended to function as the core of larger toolsets comprising model checkers, weak or branching bisimulation checkers, simulators, etc. The main problem in constructing these larger toolsets is to manage the software development process, especially, when many different people are contributing. Therefore, and this makes our approach unique, we describe specifications and implementations of the tools formally in ¯CRL. We realise the tools in C and let them communicate via the Toolbus. 1 Introduction It is a major problem to keep large software development projects manageable. Typically, such projects end up in a situation where there is a lot of code, a lot of not too consistent documentation and many experts, who all have knowledge about parts of the software. In such cases it has become rather hard to make adaptations to the software and rather expensive to train a new expe...
Building a Simulator in the mu CRL toolbox  A casestudy in modern software engineering
 of Lecture Notes in Computer Science
, 1996
"... In this paper we report on the current status of our development of a simulator tool in the CRL Toolbox. The tool is built from (reusable) software components which are implemented in different languages like C, TCL/TK and ASF+SDF. The components communicate with each other via the ToolBus which is ..."
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In this paper we report on the current status of our development of a simulator tool in the CRL Toolbox. The tool is built from (reusable) software components which are implemented in different languages like C, TCL/TK and ASF+SDF. The components communicate with each other via the ToolBus which is a new software architecture for building large, heterogeneous and distributed systems. AMS Subject Classification (1991): 68N15, 68Q60. CR Subject Classification (1991): D.2.1, D.2.2, D.2.6. Keywords & Phrases: CRL, simulator, ToolBus. 1 Introduction It is a major problem to keep large software projects manageable. Typically, such projects end up in a situation where there is a lot of code, a lot of inconsistent documentation and many experts who have knowledge about parts of the software. In such situation, it is rather hard to adapt the software and rather expensive to train new experts. This makes the maintenance of software a costly operation. At the CWI where we are developing a to...