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A calculus of mobile processes, I
, 1992
"... We present the acalculus, a calculus of communicating systems in which one can naturally express processes which have changing structure. Not only may the component agents of a system be arbitrarily linked, but a communication between neighbours may carry information which changes that linkage. The ..."
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Cited by 1184 (31 self)
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We present the acalculus, a calculus of communicating systems in which one can naturally express processes which have changing structure. Not only may the component agents of a system be arbitrarily linked, but a communication between neighbours may carry information which changes that linkage. The calculus is an extension of the process algebra CCS, following work by Engberg and Nielsen, who added mobility to CCS while preserving its algebraic properties. The rrcalculus gains simplicity by removing all distinction between variables and constants; communication links are identified by names, and computation is represented purely as the communication of names across links. After an illustrated description of how the ncalculus generalises conventional process algebras in treating mobility, several examples exploiting mobility are given in some detail. The important examples are the encoding into the ncalculus of higherorder functions (the Icalculus and combinatory algebra), the transmission of processes as values, and the representation of data structures as processes. The paper continues by presenting the algebraic theory of strong bisimilarity and strong equivalence, including a new notion of equivalence indexed by distinctionsi.e., assumptions of inequality among names. These theories are based upon a semantics in terms of a labeled transition system and a notion of strong bisimulation, both of which are expounded in detail in a companion paper. We also report briefly on workinprogress based upon the corresponding notion of weak bisimulation, in which internal actions cannot be observed.
Typing and Subtyping for Mobile Processes
 MATHEMATICAL STRUCTURES IN COMPUTER SCIENCE
, 1996
"... The picalculus is a process algebra that supports process mobility by focusing on the communication of channels. Milner's ..."
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Cited by 276 (18 self)
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The picalculus is a process algebra that supports process mobility by focusing on the communication of channels. Milner's
A Calculus of Mobile Processes, Part I
 I AND II. INFORMATION AND COMPUTATION
, 1989
"... We present the ßcalculus, a calculus of communicating systems in which one can naturally express processes which have changing structure. Not only may the component agents of a system be arbitrarily linked, but a communication between neighbours may carry information which changes that linkage. The ..."
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Cited by 219 (4 self)
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We present the ßcalculus, a calculus of communicating systems in which one can naturally express processes which have changing structure. Not only may the component agents of a system be arbitrarily linked, but a communication between neighbours may carry information which changes that linkage. The calculus is an extension of the process algebra CCS, following work by Engberg and Nielsen who added mobility to CCS while preserving its algebraic properties. The ßcalculus gains simplicity by removing all distinction between variables and constants; communication links are identified by names, and computation is represented purely as the communication of names across links. After an illustrated description of how the ßcalculus generalises conventional process algebras in treating mobility, several examples exploiting mobility are given in some detail. The important examples are the encoding into the ß calculus of higherorder functions (the calculus and combinatory algebra), the tr...
On reductionbased process semantics
 in Proceedings of FSTTCS ’93, LNCS 761
, 1995
"... Abstract. A formulation of semantic theories for processes which is based on reduction relation and equational reasoning is studied. The new construction can induce meaningful theories for processes, both in strong and weak settings. The resulting theories in many cases coincide with, and sometimes ..."
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Cited by 160 (27 self)
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Abstract. A formulation of semantic theories for processes which is based on reduction relation and equational reasoning is studied. The new construction can induce meaningful theories for processes, both in strong and weak settings. The resulting theories in many cases coincide with, and sometimes generalise, observationbased formulation of behavioural equivalence. The basic construction of reductionbased theories is studied, taking a simple name passing calculus called $\nu$calculus as an example. Results on other calculi are also briefly discussed. 1
Types for Dyadic Interaction
, 1993
"... We formulate a typed formalism for concurrency where types denote freely composable structure of dyadic interaction in the symmetric scheme. The resulting calculus is a typed reconstruction of name passing process calculi. Systems with both the explicit and implicit typing disciplines, where types f ..."
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Cited by 137 (11 self)
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We formulate a typed formalism for concurrency where types denote freely composable structure of dyadic interaction in the symmetric scheme. The resulting calculus is a typed reconstruction of name passing process calculi. Systems with both the explicit and implicit typing disciplines, where types form a simple hierarchy of types, are presented, which are proved to be in accordance with each other. A typed variant of bisimilarity is formulated and it is shown that typed fiequality has a clean embedding in the bisimilarity. Name reference structure induced by the simple hierarchy of types is studied, which fully characterises the typable terms in the set of untyped terms. It turns out that the name reference structure results in the deadlockfree property for a subset of terms with a certain regular structure, showing behavioural significance of the simple type discipline. 1 Introduction This is a preliminary study of types for concurrency. Types here denote freely composable structur...
An Asynchronous Model of Locality, Failure, and Process Mobility
 THEORETICAL COMPUTER SCIENCE
, 1997
"... We present a model of distributed computation which is based on a fragment of the picalculus relying on asynchronous communication. We enrich the model with the following features: the explicit distribution of processes to locations, the failure of locations and their detection, and the mobility of ..."
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Cited by 116 (4 self)
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We present a model of distributed computation which is based on a fragment of the picalculus relying on asynchronous communication. We enrich the model with the following features: the explicit distribution of processes to locations, the failure of locations and their detection, and the mobility of processes. Our contributions are two folds. At the specification level, we give a synthetic and flexible formalization of the features mentioned above. At the verification level, we provide original methods to reason about the bisimilarity of processes in the presence of failures.
A brief history of process algebra
 THEOR. COMPUT. SCI
, 2004
"... This note addresses the history of process algebra as an area of research in concurrency theory, the theory of parallel and distributed systems in computer science. Origins are traced back to the early seventies of the twentieth century, and developments since that time are sketched. The author giv ..."
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Cited by 84 (1 self)
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This note addresses the history of process algebra as an area of research in concurrency theory, the theory of parallel and distributed systems in computer science. Origins are traced back to the early seventies of the twentieth century, and developments since that time are sketched. The author gives his personal views on these matters. He also considers the present situation, and states some challenges for the future.
Testing equivalence for mobile processes
 Proceedings of CONCUR ’92, LNCS 630
, 1995
"... Abst rac t. The impact of applying the testing approach to a calculus of processes with a dynamically changing structure is investigated. A proof system for the finite fragment of the calculus is introduced which consists of two groups of laws: those for strong observational equivalence and those ne ..."
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Cited by 71 (10 self)
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Abst rac t. The impact of applying the testing approach to a calculus of processes with a dynamically changing structure is investigated. A proof system for the finite fragment of the calculus is introduced which consists of two groups of laws: those for strong observational equivalence and those needed to deal with x actions. Soundness and completeness w.r.t, a testing preorder are shown. A fully abstract denotational model for the language is presented which relies on the existence of normal forms for processes. 1.
ComponentOriented Software Technology
, 1995
"... Modern software systems are increasingly required to be open and distributed. Such systems are open not only in terms of network connectR06 andint0 operabilit support forhet1 ogeneous hardware andsoft are plat orms,but above all, int2 ms of evolving and changingrequirement . Alt169, object,7 ient3 t ..."
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Cited by 60 (9 self)
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Modern software systems are increasingly required to be open and distributed. Such systems are open not only in terms of network connectR06 andint0 operabilit support forhet1 ogeneous hardware andsoft are plat orms,but above all, int2 ms of evolving and changingrequirement . Alt169, object,7 ient3 t331,7E8 offers some relief,t o a largeext27 t he languages,met2R8 andtd,2 fail t addresstd needs of opensystE3 becausetc y donot escape from tadit192, models of soft are development tpm assume syst, requirement t be closed and st ble.We argue te, open systE8 requirement can only beadequat7E addressed byadopt9, a component,t ient0 as opposedt a purelyobject3E ient2 soft are development approach, byshift7, emphasis away from programming and towards generalized software composition.