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19
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.
πCalculus, Internal Mobility, and AgentPassing Calculi
 THEORETICAL COMPUTER SCIENCE
, 1995
"... The πcalculus is a process algebra which originates from CCS and permits a natural modelling of mobility (i.e., dynamic reconfigurations of the process linkage) using communication of names. Previous research has shown that the πcalculus has much greater expressiveness than CCS, but also a much mo ..."
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Cited by 80 (11 self)
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The πcalculus is a process algebra which originates from CCS and permits a natural modelling of mobility (i.e., dynamic reconfigurations of the process linkage) using communication of names. Previous research has shown that the πcalculus has much greater expressiveness than CCS, but also a much more complex mathematical theory. The primary goal of this work is to understand the reasons of this gap. Another goal is to compare the expressiveness of namepassing calculi, i.e., calculi like πcalculus where mobility is achieved via exchange of names, and that of agentpassing calculi, i.e., calculi where mobility is achieved via exchange of agents. We separate the mobility mechanisms of the πcalculus into two, respectively called internal mobility and external mobility. The study of the subcalculus which only uses internal mobility, called I, suggests that internal mobility is responsible for much of the expressiveness of the πcalculus, whereas external mobility is responsible for many of...
A Compositional Logic for Proving Security Properties of Protocols
 Journal of Computer Security
, 2002
"... We present a logic for proving security properties of protocols that use nonces (randomly generated numbers that uniquely identify a protocol session) and publickey cryptography. The logic, designed around a process calculus with actions for each possible protocol step, consists of axioms about ..."
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Cited by 50 (12 self)
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We present a logic for proving security properties of protocols that use nonces (randomly generated numbers that uniquely identify a protocol session) and publickey cryptography. The logic, designed around a process calculus with actions for each possible protocol step, consists of axioms about protocol actions and inference rules that yield assertions about protocols composed of multiple steps. Although assertions are written using only steps of the protocol, the logic is sound in a stronger sense: each provable assertion about an action or sequence of actions holds in any run of the protocol that contains the given actions and arbitrary additional actions by a malicious attacker. This approach lets us prove security properties of protocols under attack while reasoning only about the sequence of actions taken by honest parties to the protocol. The main securityspecific parts of the proof system are rules for reasoning about the set of messages that could reveal secret data and an invariant rule called the "honesty rule." 1
A Compositional Logic for Protocol Correctness
 In Proceedings of 14th IEEE Computer Security Foundations Workshop
, 2001
"... We present a specialized protocol logic that is built around a process language for describing the actions of a protocol. In general terms, the relation between logic and protocol is like the relation between assertions in FloydHoare logic and standard imperative programs. Like FloydHoare logic, o ..."
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Cited by 33 (14 self)
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We present a specialized protocol logic that is built around a process language for describing the actions of a protocol. In general terms, the relation between logic and protocol is like the relation between assertions in FloydHoare logic and standard imperative programs. Like FloydHoare logic, our logic contains axioms and inference rules for each of the main protocol actions and proofs are protocoldirected, meaning that the outline of a proof of correctness follows the sequence of actions in the protocol. We prove that the protocol logic is sound, in a specific sense: each provable assertion about an action or sequence of actions holds in any run of the protocol, under attack, in which the given actions occur. This approach lets us prove properties of protocols that hold in all runs, while explicitly reasoning only about the sequence of actions needed to achieve this property. In particular, no explicit reasoning about the potential actions of an attacker is required.
Categorical Logic of Names and Abstraction in Action Calculi
, 1993
"... ion elimination Definition 3.1. A monoidal category where every object has a commutative comonoid structure is said to be semicartesian. An action category is a K\Omega category with a distinguished admissible commutative comonoid structure on every object. A semicartesian category is cartesi ..."
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Cited by 21 (9 self)
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ion elimination Definition 3.1. A monoidal category where every object has a commutative comonoid structure is said to be semicartesian. An action category is a K\Omega category with a distinguished admissible commutative comonoid structure on every object. A semicartesian category is cartesian if and only if each object carries a unique comonoid structure, and such structures form two natural families, \Delta and !. The naturality means that all morphisms of the category must be comonoid homomorphisms. In action categories, the property of semicartesianness is fixed as structure: on each object, a particular comonoid structure is chosen. This choice may be constrained by some given graphic operations, with respect to which the structures must be admissible. The proof of proposition 2.6 shows that such structures determine the abstraction operators, and are determined by them. This is the essence of the equivalence of action categories and action calculi. As the embodiment of 2...
HighLevel Petri Nets as Type Theories in the Join Calculus
 In Proceedings FOSSACS 2001, volume 2030 of LNCS
, 2001
"... Abstract. We study the expressiveness of the join calculus by comparison with (generalised, coloured) Petri nets and using tools from type theory. More precisely, we consider four classes of nets of increasing expressiveness, Πi, introduce a hierarchy of type systems of decreasing strictness, ∆i, i ..."
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Cited by 20 (0 self)
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Abstract. We study the expressiveness of the join calculus by comparison with (generalised, coloured) Petri nets and using tools from type theory. More precisely, we consider four classes of nets of increasing expressiveness, Πi, introduce a hierarchy of type systems of decreasing strictness, ∆i, i =0,...,3, and we prove that a join process is typeable according to ∆i if and only if it is (strictly equivalent to) a net of class Πi. In the details, Π0 and Π1 contain, resp., usual place/transition and coloured Petri nets, while Π2 and Π3 propose two natural notions of highlevel net accounting for dynamic reconfiguration and process creation and called reconfigurable and dynamic Petri nets, respectively. 1
Strategic Directions in Concurrency Research
 ACM COMPUTING SURVEYS
, 1996
"... Concurrency is concerned with the fundamental aspects of systems of multiple, simultaneously active computing agents that interact with one another. This notion is ..."
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Cited by 14 (0 self)
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Concurrency is concerned with the fundamental aspects of systems of multiple, simultaneously active computing agents that interact with one another. This notion is
Characterizing behavioural congruences for Petri nets
 Proc. CONCUR’95, LNCS 962
, 1995
"... Abstract. We exploit a notion of interface for Petri nets in order to design a set of net combinators. For such a calculus of nets, we focus on the behavioural congruences arising from four simple notions of behaviour, viz., traces, maximal traces, step, and maximal step traces, and from the corresp ..."
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Cited by 13 (3 self)
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Abstract. We exploit a notion of interface for Petri nets in order to design a set of net combinators. For such a calculus of nets, we focus on the behavioural congruences arising from four simple notions of behaviour, viz., traces, maximal traces, step, and maximal step traces, and from the corresponding four notions of bisimulation, viz., weak and weak step bisimulation and their maximal versions. We characterize such congruences via universal contexts and via games, providing in such a way an understanding of their discerning powers.
Socially Responsive, Environmentally Friendly Logic
 in Truth and Games: Essays in Honour of Gabriel Sandu, Aho, Tuomo and AhtiVeikko Pietarinen, eds., Acta Philosophica Fennica
, 2006
"... We consider the following questions: What kind of logic has a natural semantics in multiplayer (rather than 2player) games? How can we express branching quantifiers, and other partialinformation constructs, with a properly compositional syntax and semantics? We develop a logic in answer to these ..."
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Cited by 7 (0 self)
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We consider the following questions: What kind of logic has a natural semantics in multiplayer (rather than 2player) games? How can we express branching quantifiers, and other partialinformation constructs, with a properly compositional syntax and semantics? We develop a logic in answer to these questions, with a formal semantics based on multiple concurrent strategies, formalized as closure operators on KahnPlotkin concrete domains. Partial information constraints are represented as coclosure operators. We address the syntactic issues by treating syntactic constituents, including quantifiers, as arrows in a category, with arities and coarities. This enables a fully compositional account of a wide