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48
On the expressiveness of linearity vs persistence in the asychronous picalculus
 In Proc. of LICS’06. IEEE Computer Society
, 2006
"... We present an expressiveness study of linearity and persistence of processes. We choose the πcalculus, one of the main representatives of process calculi, as a framework to conduct our study. We consider four fragments of the πcalculus. Each one singles out a natural source of linearity/persistenc ..."
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Cited by 8 (2 self)
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We present an expressiveness study of linearity and persistence of processes. We choose the πcalculus, one of the main representatives of process calculi, as a framework to conduct our study. We consider four fragments of the πcalculus. Each one singles out a natural source of linearity/persistence also present in other frameworks such as Concurrent Constraint Programming (CCP), Linear CCP, and several calculi for security. The study is presented by providing (or proving the nonexistence of) encodings among the fragments, a processesasformulae interpretation and a reduction from Minsky machines. 1
Symmetric electoral systems for ambient calculi
 Information & Computation. Accepted
"... This paper compares the expressiveness of different fragments of ambient calculi via ..."
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This paper compares the expressiveness of different fragments of ambient calculi via
On Synchronous and Asynchronous Communication Paradigms
 Proc. of ICTCS ’01, LNCS
, 2000
"... The πcalculus, its asynchronous version and Boudol’s mapping from the former language to the latter one are wellknown mathematical objects in theoretical computer science. It is also wellknown that the mapping is not fullyabstract w.r.t. most of the semantics defined over these two languages. In ..."
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Cited by 4 (1 self)
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The πcalculus, its asynchronous version and Boudol’s mapping from the former language to the latter one are wellknown mathematical objects in theoretical computer science. It is also wellknown that the mapping is not fullyabstract w.r.t. most of the semantics defined over these two languages. In this paper we study and fix conditions on the existence of fullyabstract results for Boudol’s mapping (and its variants). The testing theories à la De NicolaHennessy turned out to be very useful tools for such a purpose. 1
A Randomized Encoding of the πCalculus with Mixed Choice
, 2001
"... We consider the problem of encoding the calculus with mixed choice into the asynchronous calculus via a uniform translation while preserving a reasonable semantics. Although it has been shown that this is not possible with an exact encoding, we suggest a randomized approach using a probabilisti ..."
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Cited by 4 (1 self)
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We consider the problem of encoding the calculus with mixed choice into the asynchronous calculus via a uniform translation while preserving a reasonable semantics. Although it has been shown that this is not possible with an exact encoding, we suggest a randomized approach using a probabilistic extension of the asynchronous calculus, and we show that our solution is correct with probability 1 under any proper adversary wrt a notion of testing semantics. This result establishes the basis for a distributed and symmetric implementation of mixed choice which, differently from previous proposals in literature, does not rely on assumptions on the relative speed of processes and is robust to attacks of (fair) adversaries.
C.: Explicit fairness in testing semantics
 Logical Methods in Computer Science 5(2
, 2009
"... address: ..."
On the Benefits of Using the UpTo Techniques for Bisimulation Verification
"... We advocate the use of the up to techniques for bisimulation in the field of automatic verification. To this end, we develop a tool to perform proofs using the up to structural congruence, the up to restrictions and the up to parallel composition proof techniques for bisimulation between calculus te ..."
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Cited by 3 (0 self)
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We advocate the use of the up to techniques for bisimulation in the field of automatic verification. To this end, we develop a tool to perform proofs using the up to structural congruence, the up to restrictions and the up to parallel composition proof techniques for bisimulation between calculus terms. The latter technique is of particular interest because it allows one to reason on infinite state space processes. To use it in full effect, we adapt the on the fly bisimulation checking algorithm, leading to a form of computational completeness. The usefulness of these techniques in dealing with the expressive power of the calculus is illustrated on two non trivial examples, namely the treatment of persistent data structures and the alternating bit protocol. These examples are also good opportunities to study how well known calculus encodings behave in the framework of automatic verification.
On the Expressive Power of Global and Local Priority in Process Calculi
"... Priority is a frequently used feature of many computational systems. In this paper we study the expressiveness of two process algebras enriched with different priority mechanisms. In particular, we consider a finite (i.e. recursionfree) fragment of asynchronous CCS with global priority (FAP, for sh ..."
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Cited by 3 (2 self)
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Priority is a frequently used feature of many computational systems. In this paper we study the expressiveness of two process algebras enriched with different priority mechanisms. In particular, we consider a finite (i.e. recursionfree) fragment of asynchronous CCS with global priority (FAP, for short) and Phillips ’ CPG (CCS with local priority), and we contrast their expressive power with that of two nonprioritised calculi, namely the πcalculus and its broadcastbased version, called bπ. We prove, by means of leaderelectionbased separation results, that there exists no encoding of FAP into πCalculus or CPG, under certain conditions. Moreover, we single out another problem in distributed computing, we call the last man standing problem (LMS for short), that better reveals the gap between the two prioritised calculi above and the two non prioritised ones, by proving that there exists no parallelpreserving encoding of the prioritised calculi into the nonprioritised calculi retaining any sincere (complete but partially correct, i.e., admitting divergence or premature termination) semantics. 1
Symmetric and Asymmetric Asynchronous Interaction
"... We investigate classes of systems based on different interaction patterns with the aim of achieving distributability. As our system model we use Petri nets. In Petri nets, an inherent concept of simultaneity is built in, since when a transition has more than one preplace, it can be crucial that toke ..."
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We investigate classes of systems based on different interaction patterns with the aim of achieving distributability. As our system model we use Petri nets. In Petri nets, an inherent concept of simultaneity is built in, since when a transition has more than one preplace, it can be crucial that tokens are removed instantaneously. When modelling a system which is intended to be implemented in a distributed way by a Petri net, this builtin concept of synchronous interaction may be problematic. To investigate the problem we assume that removing tokens from places can no longer be considered as instantaneous. We model this by inserting silent (unobservable) transitions between transitions and their preplaces. We investigate three different patterns for modelling this type of asynchronous interaction. Full asynchrony assumes that every removal of a token from a place is time consuming. For symmetric asynchrony, tokens are only removed slowly in case of backward branched transitions, hence where the concept of simultaneous removal actually occurs. Finally we consider a more intricate pattern by allowing to remove tokens from preplaces of backward branched transitions asynchronously in sequence (asymmetric asynchrony). We investigate the effect of these different transformations of instantaneous interaction into asynchronous interaction patterns by comparing the behaviours of nets before and after insertion of the silent transitions. We exhibit for which classes of Petri nets we obtain equivalent behaviour with respect to failures equivalence. It turns out that the resulting hierarchy of Petri net classes can be described by semistructural properties. In case of full asynchrony and symmetric asynchrony, we obtain precise characterisations; for asymmetric asynchrony we obtain lower and upper bounds. We briefly comment on possible applications of our results to Message Sequence Charts.
A Randomized Distributed Encoding of the πCalculus with Mixed Choice
, 2002
"... We consider the problem of encoding the calculus (more precisely, the version of the calculus with mixed choice) into the asynchronous calculus via a uniform translation preserving a reasonable semantics. Although it has been shown that this is not possible with an exact encoding, we suggest a ra ..."
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Cited by 2 (0 self)
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We consider the problem of encoding the calculus (more precisely, the version of the calculus with mixed choice) into the asynchronous calculus via a uniform translation preserving a reasonable semantics. Although it has been shown that this is not possible with an exact encoding, we suggest a randomized approach using a probabilistic extension of the asynchronous calculus, and we show that our solution is correct with probability 1 under any proper adversary wrt a notion of testing semantics. This result establishes the basis for a distributed and symmetric implementation of mixed choice which, differently from previous proposals in literature, does not rely on assumptions on the relative speed of processes and is robust to attacks of proper adversaries.