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Operational congruences for reactive systems
, 2001
"... This document consists of a slightly revised and corrected version of a dissertation ..."
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Cited by 34 (4 self)
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This document consists of a slightly revised and corrected version of a dissertation
A congruence rule format for namepassing process calculi from mathematical structural operational semantics
 In Proc. LICS’06
, 2006
"... We introduce a GSOSlike rule format for namepassing process calculi. Specifications in this format correspond to theories in nominal logic. The intended models of such specifications arise by initiality from a general categorical model theory. For operational semantics given in this rule format, a ..."
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Cited by 20 (5 self)
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We introduce a GSOSlike rule format for namepassing process calculi. Specifications in this format correspond to theories in nominal logic. The intended models of such specifications arise by initiality from a general categorical model theory. For operational semantics given in this rule format, a natural behavioural equivalence — a form of open bisimilarity — is a congruence.
The UDP Calculus: Rigorous Semantics for Real Networking
, 2001
"... Network programming is notoriously hard to understand: one has to deal with a variety of protocols (IP, ICMP, UDP, TCP etc), concurrency, packet loss, host failure, timeouts, the complex sockets interface to the protocols, and subtle portability issues. Moreover, the behavioural properties of ope ..."
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Cited by 19 (15 self)
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Network programming is notoriously hard to understand: one has to deal with a variety of protocols (IP, ICMP, UDP, TCP etc), concurrency, packet loss, host failure, timeouts, the complex sockets interface to the protocols, and subtle portability issues. Moreover, the behavioural properties of operating systems and the network are not well documented.
Model checking for nominal calculi
 IN FOSSACS, VOLUME 3441 OF LNCS
, 2005
"... Nominal calculi have been shown very effective to formally model a variety of computational phenomena. The models of nominal calculi have often infinite states, thus making model checking a difficult task. In this note we survey some of the approaches for model checking nominal calculi. Then, we f ..."
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Cited by 6 (2 self)
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Nominal calculi have been shown very effective to formally model a variety of computational phenomena. The models of nominal calculi have often infinite states, thus making model checking a difficult task. In this note we survey some of the approaches for model checking nominal calculi. Then, we focus on HistoryDependent automata, a syntaxfree automatonbased model of mobility. HistoryDependent automata have provided the formal basis to design and implement some existing verification toolkits. We then introduce a novel syntaxfree setting to model the symbolic semantics of a nominal calculus. Our approach relies on the notions of reactive systems and observed borrowed contexts introduced by Leifer and Milner, and further developed by Sassone, Lack and Sobocinski. We argue that the symbolic semantics model based on borrowed contexts can be conveniently applied to web service discovery and binding.
Typed event Structures and the πcalculus
 In Proc. MFPS’06
, 2006
"... Abstract. We propose a typing system for the true concurrent model of event structures that guarantees an interesting behavioural property known as confusion freeness. A system is confusion free if nondeterministic choices are localised and do not depend on the scheduling of independent components. ..."
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Cited by 5 (3 self)
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Abstract. We propose a typing system for the true concurrent model of event structures that guarantees an interesting behavioural property known as confusion freeness. A system is confusion free if nondeterministic choices are localised and do not depend on the scheduling of independent components. It is a generalisation of confluence to systems that allow nondeterminism. Ours is the first typing system to control behaviour in a true concurrent model. To demonstrate its applicability, we show that typed event structures give a semantics of linearly typed version of the πcalculi with internal mobility. The semantics we provide is the first event structure semantics of the πcalculus and generalises Winskel’s original event structure semantics of CCS. 1
Applying Petri Net Unfoldings for Verification of Mobile Systems
 In MOCA 2006
, 2006
"... Summary. Mobility is a central feature of many distributed systems of ever growing complexity. To make their formal analysis and verification feasible, process algebras — notably the πcalculus — have been introduced and extensively studied. A wellestablished method of verifying the correctness of ..."
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Cited by 3 (2 self)
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Summary. Mobility is a central feature of many distributed systems of ever growing complexity. To make their formal analysis and verification feasible, process algebras — notably the πcalculus — have been introduced and extensively studied. A wellestablished method of verifying the correctness of general distributed systems has been modelchecking which is completely automatic and relatively fast compared to other alternatives, and so particularly attractive in industrial context. Mobile systems are highly concurrent causing state space explosion when applying modelchecking techniques. To cope with this problem, techniques based on partial order semantics of concurrency seem to offer the desired level of efficiency. The aim of this paper is to investigate how one of such techniques — based of unfoldings of highlevel Petri nets — could be used for verification of πcalculus terms. Our starting point was an existing compositional translation from a finite fragment of the πcalculus into a class of highlevel Petri nets. We developed a prototype tool based on this theoretical translation and an existing efficient unfolder and verifier. In this paper, we describe initial experimental results in support of specific design choices. Crucially, developing the prototype was not a straightforward task since the theoretical translation does not produce nets which conform to the input format required by the verifier. The paper states how this mismatch has been overcome and draws conclusions for future uses of unfoldings technique in the modelchecking of mobile systems.
Compositional Event Structure Semantics for the Internal πCalculus ⋆
"... Abstract. We propose the first compositional event structure semantics for a very expressive πcalculus, generalising Winskel’s event structures for CCS. The πcalculus we model is the πIcalculus with recursive definitions and summations. First we model the synchronous calculus, introducing a notio ..."
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Cited by 3 (0 self)
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Abstract. We propose the first compositional event structure semantics for a very expressive πcalculus, generalising Winskel’s event structures for CCS. The πcalculus we model is the πIcalculus with recursive definitions and summations. First we model the synchronous calculus, introducing a notion of dynamic renaming to the standard operators on event structures. Then we model the asynchronous calculus, for which a new additional operator, called rooting, is necessary for representing causality due to new name binding. The semantics are shown to be operationally adequate and sound with respect to bisimulation. 1
Compositional Event Structure Semantics for the πCalculus
"... Abstract. We propose the first compositional event structure semantics for a fully expressive πcalculus, generalising Winskel’s event structures for CCS. The πcalculus we model is the πIcalculus with recursive definitions and summations. First we model the synchronous calculus, introducing a noti ..."
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Abstract. We propose the first compositional event structure semantics for a fully expressive πcalculus, generalising Winskel’s event structures for CCS. The πcalculus we model is the πIcalculus with recursive definitions and summations. First we model the synchronous calculus, introducing a notion of dynamic renaming to the standard operators on event structures. Then we model the asynchronous calculus, for which a new additional operator, called rooting, is necessary for representing causality due to new name binding. The semantics are shown to be operationally adequate and sound with respect to bisimulation. 1
Modelling Fusion calculus using HDautomata ⋆
"... Abstract. We propose a coalgebraic model of the Fusion calculus based on HDautomata. The main advantage of the approach is that the partition refinement algorithm designed for HDautomata is easily adapted to handle Fusion calculus processes. Hence, the transition systems of Fusion calculus process ..."
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Cited by 2 (0 self)
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Abstract. We propose a coalgebraic model of the Fusion calculus based on HDautomata. The main advantage of the approach is that the partition refinement algorithm designed for HDautomata is easily adapted to handle Fusion calculus processes. Hence, the transition systems of Fusion calculus processes can be minimised according to the notion of observational semantics of the calculus. As a beneficial side effect, this also provides a bisimulation checker for Fusion calculus. 1
Reactive Systems, (Semi)Saturated Semantics and Coalgebras on Presheaves
, 2009
"... The semantics of process calculi has traditionally been specified by labelled transition systems (ltss), but with the development of name calculi it turned out that reaction rules (i.e., unlabelled transition rules) are often more natural. This leads to the question of how behavioural equivalences ( ..."
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The semantics of process calculi has traditionally been specified by labelled transition systems (ltss), but with the development of name calculi it turned out that reaction rules (i.e., unlabelled transition rules) are often more natural. This leads to the question of how behavioural equivalences (bisimilarity, trace equivalence, etc.) defined for lts can be transferred to unlabelled transition systems. Recently, in order to answer this question, several proposals have been made with the aim of automatically deriving an lts from reaction rules in such a way that the resulting equivalences are congruences. Furthermore these equivalences should agree with the standard semantics, whenever one exists. In this paper we propose saturated semantics, based on a weaker notion of observation and orthogonal to all the previous proposals, and we demonstrate the appropriateness of our semantics by means of two examples: logic programming and open Petri nets. We also show that saturated semantics can be efficiently characterized through the so called semisaturated games. Finally, we provide coalgebraic models relying on presheaves.