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Comparing the Expressive Power of the Synchronous and the Asynchronous picalculi
, 2002
"... this paper we focus on the distinction between synchronous and asynchronous. Synchronous communication is usually understood as simultaneous exchange of information between the partners; a"real life" example is the telephone . In contrast, in asynchronous communication the action of sen ..."
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Cited by 179 (25 self)
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this paper we focus on the distinction between synchronous and asynchronous. Synchronous communication is usually understood as simultaneous exchange of information between the partners; a"real life" example is the telephone . In contrast, in asynchronous communication the action of sending a message and the action of reading it Work supported by the NSFPOWRE grant EIA0074909
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 119 (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.
On Asynchrony in NamePassing Calculi
 In
, 1998
"... The asynchronous picalculus is considered the basis of experimental programming languages (or proposal of programming languages) like Pict, Join, and Blue calculus. However, at a closer inspection, these languages are based on an even simpler calculus, called Local (L), where: (a) only the output c ..."
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Cited by 98 (15 self)
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The asynchronous picalculus is considered the basis of experimental programming languages (or proposal of programming languages) like Pict, Join, and Blue calculus. However, at a closer inspection, these languages are based on an even simpler calculus, called Local (L), where: (a) only the output capability of names may be transmitted; (b) there is no matching or similar constructs for testing equality between names. We study the basic operational and algebraic theory of Lpi. We focus on bisimulationbased behavioural equivalences, precisely on barbed congruence. We prove two coinductive characterisations of barbed congruence in Lpi, and some basic algebraic laws. We then show applications of this theory, including: the derivability of delayed input; the correctness of an optimisation of the encoding of callbyname lambdacalculus; the validity of some laws for Join.
The πCalculus in Direct Style
, 1997
"... We introduce a calculus which is a direct extension of both the and the π calculi. We give a simple type system for it, that encompasses both Curry's type inference for the calculus, and Milner's sorting for the πcalculus as particular cases of typing. We observe that the various contin ..."
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Cited by 70 (2 self)
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We introduce a calculus which is a direct extension of both the and the π calculi. We give a simple type system for it, that encompasses both Curry's type inference for the calculus, and Milner's sorting for the πcalculus as particular cases of typing. We observe that the various continuation passing style transformations for terms, written in our calculus, actually correspond to encodings already given by Milner and others for evaluation strategies of terms into the πcalculus. Furthermore, the associated sortings correspond to wellknown double negation translations on types. Finally we provide an adequate cps transform from our calculus to the πcalculus. This shows that the latter may be regarded as an "assembly language", while our calculus seems to provide a better programming notation for higherorder concurrency.
Session Types as Intuitionistic Linear Propositions
"... Several type disciplines for πcalculi have been proposed in which linearity plays a key role, even if their precise relationship with pure linear logic is still not well understood. In this paper, we introduce a type system for the πcalculus that exactly corresponds to the standard sequent calculu ..."
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Cited by 61 (17 self)
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Several type disciplines for πcalculi have been proposed in which linearity plays a key role, even if their precise relationship with pure linear logic is still not well understood. In this paper, we introduce a type system for the πcalculus that exactly corresponds to the standard sequent calculus proof system for dual intuitionistic linear logic. Our type system is based on a new interpretation of linear propositions as session types, and provides the first purely logical account of all (both shared and linear) features of session types. We show that our type discipline is useful from a programming perspective, and ensures session fidelity, absence of deadlocks, and a tight operational correspondence between πcalculus reductions and cut elimination steps. 1
Bisimulations in the joincalculus
 Theoretical Computer Science
, 1998
"... We propose an objectoriented calculus with internal concurrency and classbased inheritance that is built upon the join calculus. Method calls, locks, and states are handled in a uniform manner, using asynchronous messages. Classes are partial message definitions that can be combined and transforme ..."
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Cited by 53 (7 self)
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We propose an objectoriented calculus with internal concurrency and classbased inheritance that is built upon the join calculus. Method calls, locks, and states are handled in a uniform manner, using asynchronous messages. Classes are partial message definitions that can be combined and transformed. We design operators for behavioral and synchronization inheritance. We also give a type system that statically enforces basic safety properties. Our model is compatible with the JoCaml implementation
Towards a unified approach to encodability and separation results for process calculi
 Proc. of 19th International Conference on Concurrency Theory (CONCUR’08), number 5201 in LNCS
, 2008
"... Abstract. In this paper, we present a unified approach to evaluating the relative expressive power of process calculi. In particular, we identify a small set of criteria (that have already been somehow presented in the literature) that an encoding should satisfy to be considered a good means for lan ..."
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Cited by 35 (6 self)
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Abstract. In this paper, we present a unified approach to evaluating the relative expressive power of process calculi. In particular, we identify a small set of criteria (that have already been somehow presented in the literature) that an encoding should satisfy to be considered a good means for language comparison. We argue that the combination of such criteria is a valid proposal by noting that: (i) the best known encodings appeared in the literature satisfy them; (ii) this notion is not trivial, because there exist encodings that do not satisfy all the criteria we have proposed; (iii) the best known separation results can be formulated in terms of our criteria; and (iv) some widely believed (but never formally proved) separation results can be proved by using the criteria we propose. Moreover, the way in which we prove known separation results is easier and more uniform than the way in which such results were originally proved. 1
Typing NonUniform Concurrent Objects
, 1999
"... Concurrent objects oer services nonuniformly, as the availability of a service may depend on the internal state of the object. Typesasinterfaces is an approach not suitable to model nonuniform service availability, and the messagenotunderstood communication error is, in this setting, very r ..."
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Cited by 24 (7 self)
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Concurrent objects oer services nonuniformly, as the availability of a service may depend on the internal state of the object. Typesasinterfaces is an approach not suitable to model nonuniform service availability, and the messagenotunderstood communication error is, in this setting, very restrictive. We propose a looser denition of communication error, demanding only weak fairness for the reception of messages, by not accounting as errors messages that request methods that may become enabled at some time in the future. This new notion of error detects messages that are never accepted, either because the requested method does not exists at all, or because the object is deadlocked and cannot change its state to accept the request. We formalise nonuniform concurrent objects in T yCO, a namepassing object calculus, and we ensure program safety via a type system. Types are terms of a process algebra which describe dynamic aspects of the behaviour of objects. The type sy...
Sessions and session types: an overview
 IN 6TH INTERNATIONAL WORKSHOP ON WEB SERVICES AND FORMAL METHODS (WSFM’09
, 2010
"... We illustrate the concepts of sessions and session types as they have been developed in the setting of the πcalculus. Motivated by the goal of obtaining a formalisation closer to existing standards and aiming at their enhancement and strengthening, several extensions of the original core system h ..."
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Cited by 24 (4 self)
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We illustrate the concepts of sessions and session types as they have been developed in the setting of the πcalculus. Motivated by the goal of obtaining a formalisation closer to existing standards and aiming at their enhancement and strengthening, several extensions of the original core system have been proposed, which we survey together with the embodying of sessions into functional and objectoriented languages, as well as some implementations.
Solos in concert
 IN ICALP’99, LNCS 1644:513–523
, 1999
"... We present a calculus of mobile processes without prefix or summation, and using two different encodings we show that it can express both action prefix and guarded summation. One encoding gives a strong correspondence but uses a match operator; the other yields a slightly weaker correspondence but u ..."
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Cited by 21 (4 self)
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We present a calculus of mobile processes without prefix or summation, and using two different encodings we show that it can express both action prefix and guarded summation. One encoding gives a strong correspondence but uses a match operator; the other yields a slightly weaker correspondence but uses no additional operators.