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On the Expressive Power of Polyadic Synchronisation in πCalculus
, 2003
"... We extend the πcalculus with polyadic synchronisation, a generalisation of the communication mechanism which allows channel names to be composite. We show that this operator embeds nicely in the theory of πcalculus, we suggest that it permits divergencefree encodings of distributed calculi, and w ..."
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Cited by 29 (9 self)
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We extend the πcalculus with polyadic synchronisation, a generalisation of the communication mechanism which allows channel names to be composite. We show that this operator embeds nicely in the theory of πcalculus, we suggest that it permits divergencefree encodings of distributed calculi, and we show that a limited form of polyadic synchronisation can be encoded weakly in πcalculus. After showing that matching cannot be derived in πcalculus, we compare the expressivity of polyadic synchronisation, mixed choice and matching. In particular we show that the degree of synchronisation of a language increases its expressive power by means of a separation result in the style of Palamidessi's result for mixed choice.
Presheaf Models for the piCalculus
, 1997
"... Recent work has shown that presheaf categories provide a general model of concurrency, with an inbuilt notion of bisimulation based on open maps. Here it is shown how this approach can also handle systems where the language of actions may change dynamically as a process evolves. The example is the p ..."
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Cited by 12 (4 self)
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Recent work has shown that presheaf categories provide a general model of concurrency, with an inbuilt notion of bisimulation based on open maps. Here it is shown how this approach can also handle systems where the language of actions may change dynamically as a process evolves. The example is the picalculus, a calculus for `mobile processes' whose communication topology varies as channels are created and discarded. A denotational semantics is described for the picalculus within an indexed category of profunctors; the model is fully abstract for bisimilarity, in the sense that bisimulation in the model, obtained from open maps, coincides with the usual bisimulation obtained from the operational semantics of the picalculus. While attention is concentrated on the `late' semantics of the picalculus, it is indicated how the `early' and other variants can also be captured.
A Distributed PiCalculus with Local Areas of Communication
 in: High Level Concurrent Languages
, 2001
"... This paper introduces a process calculus designed to capture the phenomenon of names which are known universally but always refer to local information. Our system extends the picalculus so that a channel name can have within its scope several disjoint local areas. Such a channel name may be used fo ..."
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Cited by 6 (0 self)
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This paper introduces a process calculus designed to capture the phenomenon of names which are known universally but always refer to local information. Our system extends the picalculus so that a channel name can have within its scope several disjoint local areas. Such a channel name may be used for communication within an area, it may be sent between areas, but it cannot itself be used to transmit information from one area to another. Areas are arranged in a hierarchy of levels, distinguishing for example between a single application, a machine, or a whole network. We give an operational semantics for the calculus, and develop a type system that guarantees the proper use of channels within their local areas. We illustrate with models of an internet service protocol and a pair of distributed agents.
Nondeterministic Lazy it λcalculus VS it πcalculus
 ECOLE NORMALE SUPERIEURE
, 1993
"... We pursue the study of the embedding of the λcalculus into the πcalculus. Various λ calculi with parallel and convergence testing facilities are examined and their expressiveness compared; λj a lazy calculus augmented with a nondeterministic choice operator and a convergence testing combinator, ..."
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We pursue the study of the embedding of the λcalculus into the πcalculus. Various λ calculi with parallel and convergence testing facilities are examined and their expressiveness compared; λj a lazy calculus augmented with a nondeterministic choice operator and a convergence testing combinator, emerges as a suitable language to be encoded in π. Through the use of closures for variables and abstractions, the process of substitution in λj is managed in a semiexplicit way. The semantics associated to both λj and are based on contextual testing preorders. We define an encoding of λj into π; we prove that it is adequate with respect to those semantics. However, the encoding is not fullyadequate; standard examples show that π is still more discriminating than λj .