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15
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 88 (14 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.
Proof Techniques for Cryptographic Processes
 in 14th Annual IEEE Symposium on Logic in Computer Science
, 1999
"... Contextual equivalences for cryptographic process calculi, like the spicalculus, can be used to reason about correctness of protocols, but their definition suffers from quantification over all possible contexts. Here, we focus on two such equivalences, namely maytesting and barbed equivalence, and ..."
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Cited by 60 (8 self)
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Contextual equivalences for cryptographic process calculi, like the spicalculus, can be used to reason about correctness of protocols, but their definition suffers from quantification over all possible contexts. Here, we focus on two such equivalences, namely maytesting and barbed equivalence, and investigate tractable proof methods for them. To this aim, we design an enriched labelled transition system, where transitions are constrained by the knowledge the environment has of names and keys. The new transition system is then used to define a trace equivalence and a weak bisimulation equivalence, that avoid quantification over contexts. Our main results are soundness and completeness of trace and weak bisimulation equivalence with respect to maytesting and barbed equivalence, respectively. They lead to more direct proof methods for equivalence checking. The use of these methods is illustrated with a few examples, concerning implementation of secure channels and verification of proto...
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 50 (6 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 behavioural theory of access and mobility control in distributed systems
 THEORETICAL COMPUTER SCIENCE
, 2003
"... We define a typed bisimulation equivalence for the language Dpi, a distributed version of the πcalculus in which processes may migrate between dynamically created locations. It takes into account resource access policies, which can be implemented in Dpi using a novel form of dynamic capability type ..."
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Cited by 43 (10 self)
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We define a typed bisimulation equivalence for the language Dpi, a distributed version of the πcalculus in which processes may migrate between dynamically created locations. It takes into account resource access policies, which can be implemented in Dpi using a novel form of dynamic capability types. The equivalence, based on typed actions between configurations, is justified by showing that it is fullyabstract with respect to a natural distributed version of a contextual equivalence. In the second part
SafeDPi: A language for controlling mobile code
 In Proc. FOSSACS, LNCS 2987
, 2003
"... Abstract. safeDpi is a distributed version of the Picalculus, in which processes are located at dynamically created sites. Parametrised code may be sent between sites using socalled ports, which are essentially higherorder versions of Picalculus communication channels. A host location may protect ..."
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Cited by 43 (5 self)
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Abstract. safeDpi is a distributed version of the Picalculus, in which processes are located at dynamically created sites. Parametrised code may be sent between sites using socalled ports, which are essentially higherorder versions of Picalculus communication channels. A host location may protect itself by only accepting code which conforms to a given type associated to the incoming port. We define a sophisticated static type system for these ports, which restrict the capabilities and access rights of any processes launched by incoming code. Dependent and existential types are used to add flexibility, allowing the behaviour of these launched processes, encoded as process types, to depend on the host’s instantiation of the incoming code. We also show that a natural contextually defined behavioural equivalence can be characterised coinductively, using bisimulations based on typed actions. The characterisation is based on the idea of knowledge acquisition by a testing environment and makes explicit some of the subtleties of determining equivalence in this language of highly constrained distributed code. 1
Environmental bisimulations for higherorder languages
 In TwentySecond Annual IEEE Symposium on Logic in Computer Science
, 2007
"... Developing a theory of bisimulation in higherorder languages can be hard. Particularly challenging can be: (1) the proof of congruence, as well as enhancements of the bisimulation proof method with “upto context ” techniques, and (2) obtaining definitions and results that scale to languages with d ..."
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Cited by 35 (11 self)
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Developing a theory of bisimulation in higherorder languages can be hard. Particularly challenging can be: (1) the proof of congruence, as well as enhancements of the bisimulation proof method with “upto context ” techniques, and (2) obtaining definitions and results that scale to languages with different features. To meet these challenges, we present environmental bisimulations, a form of bisimulation for higherorder languages, and its basic theory. We consider four representative calculi: pure λcalculi (callbyname and callbyvalue), callbyvalue λcalculus with higherorder store, and then HigherOrder πcalculus. In each case: we present the basic properties of environmental bisimilarity, including congruence; we show that it coincides with contextual equivalence; we develop some upto techniques, including upto context, as examples of possible enhancements of the associated bisimulation method. Unlike previous approaches (such as applicative bisimulations, logical relations, SumiiPierceKoutavasWand), our method does not require induction/indices on evaluation derivation/steps (which may complicate the proofs of congruence, transitivity, and the combination with upto techniques), or sophisticated methods such as Howe’s for proving congruence. It also scales from the pure λcalculi to the richer calculi with simple congruence proofs. 1
Typed Behavioural Equivalences for Processes in the Presence of Subtyping
, 2002
"... We study typed behavioural equivalences for the calculus, in which the type system allows a form of subtyping. This enables processes to selectively distribute dierent capabilities on communication channels. ..."
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Cited by 31 (9 self)
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We study typed behavioural equivalences for the calculus, in which the type system allows a form of subtyping. This enables processes to selectively distribute dierent capabilities on communication channels.
Deconstructing behavioural theories of mobility
, 2008
"... Abstract. We reexamine the standard structural operational semantics of the πcalculus with the view that both process structure and contextual observational power should play roles in describing the behavioural theory. To that end we provide a decomposition of the operational semantics of π which ..."
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Cited by 11 (2 self)
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Abstract. We reexamine the standard structural operational semantics of the πcalculus with the view that both process structure and contextual observational power should play roles in describing the behavioural theory. To that end we provide a decomposition of the operational semantics of π which allows for a systematic definition of labelled transitions. These are derived from the calculus ’ underlying reduction rules by following the contextsaslabels philosophy while being presented using the structural approach. Our novel transition system refines to a composite description of the standard early lts. We generalise our technique to higherorder and asynchronous variants.
On Equators in Asynchronous Namepassing Calculi without Matching (Extended Abstract)
, 1999
"... We give a labeled characterization of barbed congruence in asynchronous calculus, which, unlike previous characterizations, does not use the matching construct. In absence of matching the observer cannot directly distinguish two names. In asynchronous calculus the fact that two names are indisting ..."
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Cited by 7 (0 self)
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We give a labeled characterization of barbed congruence in asynchronous calculus, which, unlike previous characterizations, does not use the matching construct. In absence of matching the observer cannot directly distinguish two names. In asynchronous calculus the fact that two names are indistinguishable can be modeled by means of Honda and Yoshida's notion of equator. Our labeled characterization is based on such a notion. As an application of our theory we provide a fully abstract encoding w.r.t. barbed congruence of external mobility (communication of free names) in terms of internal mobility (communication of private names).
Towards an Algebraic Theory of Typed Mobile Processes
 Theoretical Computer Science
, 2004
"... The impact of types on the algebraic theory of the πcalculus is studied. The type system has capability types. They allow one to distinguish between the ability to read from a channel, to write to a channel, and both to read and to write. They also give rise to a natural and powerful subtyping r ..."
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Cited by 6 (1 self)
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The impact of types on the algebraic theory of the πcalculus is studied. The type system has capability types. They allow one to distinguish between the ability to read from a channel, to write to a channel, and both to read and to write. They also give rise to a natural and powerful subtyping relation. Two variants...