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A Logical View Of Concurrent Constraint Programming
, 1995
"... . Concurrent Constraint Programming (CCP) has been the subject of growing interest as the focus of a new paradigm for concurrent computation. Like logic programming it claims close relations to logic. In fact CCP languages are logics in a certain sense that we make precise in this paper. In recent ..."
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Cited by 27 (4 self)
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. Concurrent Constraint Programming (CCP) has been the subject of growing interest as the focus of a new paradigm for concurrent computation. Like logic programming it claims close relations to logic. In fact CCP languages are logics in a certain sense that we make precise in this paper. In recent work it was shown that the denotational semantics of determinate concurrent constraint programming languages forms a fibred categorical structure called a hyperdoctrine, which is used as the basis of the categorical formulation of firstorder logic. What this shows is that the combinators of determinate CCP can be viewed as logical connectives. In this paper we extend these ideas to the operational semantics of such languages and thus make available similar analogies for a much broader variety of languages including indeterminate CCP languages and concurrent blockstructured imperative languages. CR Classification: F3.1, F3.2, D1.3, D3.3 Key words: Concurrent constraint programming, simula...
Reasoning about HigherOrder Processes
, 1994
"... We address the specification and verification problem for process calculi such as Chocs, CML and Facile where processes or functions are transmissible values. Our work takes place in the context of a static treatment of restriction and of a bisimulationbased semantics. As a paradigmatic and simple ..."
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Cited by 22 (9 self)
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We address the specification and verification problem for process calculi such as Chocs, CML and Facile where processes or functions are transmissible values. Our work takes place in the context of a static treatment of restriction and of a bisimulationbased semantics. As a paradigmatic and simple case we concentrate on (Plain) Chocs. We show that Chocs bisimulation can be characterized by an extension of HennessyMilner logic including a constructive implication, or function space constructor. This result is a nontrivial extension of the classical characterization result for labelled transition systems. In the second part of the paper we address the problem of developing a proof system for the verification of process specifications. Building on previous work for CCS we present an infinitary sound and complete proof system for the fragment of the calculus not handling restriction. Keywords: Higherorder process calculi; Bisimulation; Modal logics; Program specification; Program verif...
SOS formats and metatheory: 20 years after
, 2007
"... In 1981 Structural Operational Semantics (SOS) was introduced as a systematic way to define operational semantics of programming languages by a set of rules of a certain shape [G.D. Plotkin, A structural approach to operational semantics, Technical ..."
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Cited by 14 (5 self)
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In 1981 Structural Operational Semantics (SOS) was introduced as a systematic way to define operational semantics of programming languages by a set of rules of a certain shape [G.D. Plotkin, A structural approach to operational semantics, Technical
Filter Models for ConjunctiveDisjunctive λcalculi
, 1996
"... The distinction between the conjunctive nature of nondeterminism as opposed to the disjunctive character of parallelism constitutes the motivation and the starting point of the present work. λcalculus is extended with both a nondeterministic choice and a parallel operator; a notion of reduction i ..."
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Cited by 14 (6 self)
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The distinction between the conjunctive nature of nondeterminism as opposed to the disjunctive character of parallelism constitutes the motivation and the starting point of the present work. λcalculus is extended with both a nondeterministic choice and a parallel operator; a notion of reduction is introduced, extending fireduction of the classical calculus. We study type assignment systems for this calculus, together with a denotational semantics which is initially defined constructing a set semimodel via simple types. We enrich the type system with intersection and union types, dually reflecting the disjunctive and conjunctive behaviour of the operators, and we build a filter model. The theory of this model is compared both with a Morrisstyle operational semantics and with a semantics based on a notion of capabilities.
Extending Howe’s method to early bisimulations for typed mobile embedded resources with local names
 FSTTCS, LNCS 3821
, 2005
"... We extend Howe’s method to prove that inputearly strong anddelay contextual bisimulations are congruences for the Higherorder mobile embedded resources (Homer) calculus, a typed higher order process calculus with active mobile processes, nested locations and local names which conservatively exten ..."
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Cited by 13 (3 self)
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We extend Howe’s method to prove that inputearly strong anddelay contextual bisimulations are congruences for the Higherorder mobile embedded resources (Homer) calculus, a typed higher order process calculus with active mobile processes, nested locations and local names which conservatively extends the syntax and semantics of higherorder calculi such as Plain CHOCS and HOpi. We prove that the inputearly strong anddelay contextual bisimulation congruences are sound coinductive characterisations of barbed bisimulation congruence and in fact complete in the strong case. The extension of Howe’s method provides considerably simpler congruence proofs than established previously for similar calculi for mobile processes in nested locations.
Asynchronous process calculi: the firstorder and higherorder paradigms (Tutorial)
, 1999
"... We compare the firstorder and the higherorder... ..."
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Cited by 13 (0 self)
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We compare the firstorder and the higherorder...
NonDeterministic Extensions of Untyped λcalculus
 INFO. AND COMP
, 1995
"... The main concern of this paper is the study of the interplay between functionality and non determinism. Indeed the first question we ask is whether the analysis of parallelism in terms of sequentiality and non determinism, which is usual in the algebraic treatment of concurrency, remains correct in ..."
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Cited by 12 (0 self)
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The main concern of this paper is the study of the interplay between functionality and non determinism. Indeed the first question we ask is whether the analysis of parallelism in terms of sequentiality and non determinism, which is usual in the algebraic treatment of concurrency, remains correct in presence of functional application and abstraction. We identify non determinism in the setting of λcalculus with the absence of the ChurchRosser property plus the inconsistency of the equational theory obtained by the symmetric closure of the reduction relation. We argue in favour of a distinction between non determinism and parallelism, due to the conjunctive nature of the former in contrast to the disjunctive character of the latter. This is the basis of our analysis of the operational and denotational semantics of non deterministiccalculus, which is the classical calculus plus a choice operator, and of our election of bounded indeterminacy as the semantical counterpart of conjunctive non determinism. This leads to operational semantics based on...
An investigation into Functions as Processes
 In Proc. Ninth International Conference on the Mathematical Foundations of Programming Semantics (MFPS'93
, 1993
"... . In [Mil90] Milner examines the encoding of the calculus into the ßcalculus [MPW92]. The former is the universally accepted basis for computations with functions, the latter aims at being its counterpart for computations with processes. The primary goal of this paper is to continue the study of M ..."
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. In [Mil90] Milner examines the encoding of the calculus into the ßcalculus [MPW92]. The former is the universally accepted basis for computations with functions, the latter aims at being its counterpart for computations with processes. The primary goal of this paper is to continue the study of Milner's encodings. We focus mainly on the lazy calculus [Abr87]. We show that its encoding gives rise to a model, in which a weak form of extensionality holds. However the model is not fully abstract: To obtain full abstraction, we examine both the restrictive approach, in which the semantic domain of processes is cut down, and the expansive approach, in which calculus is enriched with constants to obtain a direct characterisation of the equivalence on terms induced, via the encoding, by the behavioural equivalence adopted on the processes. Our results are derived exploiting an intermediate representation of Milner's encodings into the HigherOrder ßcalculus, an !order extension of ...
A Sound Metalogical Semantics for Input/Output Effects
, 1994
"... . We study the longstanding problem of semantics for input /output (I/O) expressed using sideeffects. Our vehicle is a small higherorder imperative language, with operations for interactive character I/O and based on ML syntax. Unlike previous theories, we present both operational and denotational ..."
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Cited by 11 (2 self)
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. We study the longstanding problem of semantics for input /output (I/O) expressed using sideeffects. Our vehicle is a small higherorder imperative language, with operations for interactive character I/O and based on ML syntax. Unlike previous theories, we present both operational and denotational semantics for I/O effects. We use a novel labelled transition system that uniformly expresses both applicative and imperative computation. We make a standard definition of bisimilarity and prove it is a congruence using Howe's method. Next, we define a metalogical type theory M in which we may give a denotational semantics to O. M generalises Crole and Pitts' FIXlogic by adding in a parameterised recursive datatype, which is used to model I/O. M comes equipped both with judgements of equality of expressions, and an operational semantics; M itself is given a domaintheoretic semantics in the category CPPO of cppos (bottompointed posets with joins of !chains) and Scott continuous functions...
A Domaintheoretic Model for a Higherorder Process Calculus
 Proceedings of the 17th International Colloquium on Automata Languages and Programming
, 1996
"... In this paper we study a higherorder process calculus, a restriction of one due to Boudol, and develop an abstract, model for it. By abstract we mean that the model is constructed domaintheoretically and reflects a certain conceptual viewpoint about observability. It is not constructed from the sy ..."
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Cited by 11 (2 self)
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In this paper we study a higherorder process calculus, a restriction of one due to Boudol, and develop an abstract, model for it. By abstract we mean that the model is constructed domaintheoretically and reflects a certain conceptual viewpoint about observability. It is not constructed from the syntax of the calculus or from computation sequences. We describe a new powerdomain construction that can be given additional algebraic structure that allows one to model concurrent composition, in the same sense that Plotkin's powerdomain can have a continuous binary operation defined on it to model choice. We show that the model constructed this way is adequate with respect to the operational semantics. The model that we develop and our analysis of it is closely related to the work of Abramsky and Ong on the lazy lambda calculus. 1 Introduction A fundamental problem in the semantics of parallel programming languages is integrating concurrency with abstraction. Kahn's pioneering work on stat...