Open Bisimulation for Quantum Processes

Quantum processes describe concurrent communicating systems that may involve quantum information. We propose a notion of open bisimulation for quantum processes and show that it provides both a sound and complete proof methodology for a natural extensional behavioural equivalence between quantum processes. We also give a modal characterisation of open bisimulation, by extending the Hennessy-Milner logic to a quantum setting

Modelling MAC-Layer Communications in Wireless Systems

We present a timed process calculus for modelling wireless networks in which individual stations broadcast and receive messages; moreover the broadcasts are subject to collisions. Based on a reduction semantics for the calculus we define a contextual equivalence to compare the external behaviour of such wireless networks. Further, we construct an extensional LTS (labelled transition system) which models the activities of stations that can be directly observed by the external environment. Standard bisimulations in this LTS provide a sound proof method for proving systems contextually equivalence. We illustrate the usefulness of the proof methodology by a series of examples. Finally we show that this proof method is also complete, for a large class of systems

Characterizing contextual equivalence in calculi with passivation

AbstractWe study the problem of characterizing contextual equivalence in higher-order languages with passivation. To overcome the difficulties arising in the proof of congruence of candidate bisimilarities, we introduce a new form of labeled transition semantics together with its associated notion of bisimulation, which we call complementary semantics. Complementary semantics allows to apply the well-known Howeʼs method for proving the congruence of bisimilarities in a higher-order setting, even in the presence of an early form of bisimulation. We use complementary semantics to provide a coinductive characterization of contextual equivalence in the HOπP calculus, an extension of the higher-order π-calculus with passivation, obtaining the first result of this kind. We then study the problem of defining a more effective variant of bisimilarity that still characterizes contextual equivalence, along the lines of Sangiorgiʼs notion of normal bisimilarity. We provide partial results on this difficult problem: we show that a large class of test processes cannot be used to derive a normal bisimilarity in HOπP, but we show that a form of normal bisimilarity can be defined for HOπP without restriction

Contextual equivalence for higher-order pi-calculus revisited

The higher-order pi-calculus is an extension of the pi-calculus to allowcommunication of abstractions of processes rather than names alone. It has beenstudied intensively by Sangiorgi in his thesis where a characterisation of acontextual equivalence for higher-order pi-calculus is provided using labelledtransition systems and normal bisimulations. Unfortunately the proof techniqueused there requires a restriction of the language to only allow finite types.We revisit this calculus and offer an alternative presentation of the labelledtransition system and a novel proof technique which allows us to provide afully abstract characterisation of contextual equivalence using labelledtransitions and bisimulations for higher-order pi-calculus with recursive typesalso

Contextual equivalence for higher-order pi-calculus revisited

The higher-order pi-calculus is an extension of the pi-calculus to allow communication of abstractions of processes rather than names alone. It has been studied intensively by Sangiorgi in his thesis where a characterisation of a contextual equivalence for higher-order pi-calculus is provided using labelled transition systems and normal bisimulations. Unfortunately the proof technique used there requires a restriction of the language to only allow finite types. We revisit this calculus and offer an alternative presentation of the labelled transition system and a novel proof technique which allows us to provide a fully abstract characterisation of contextual equivalence using labelled transitions and bisimulations for higher-order pi-calculus with recursive types also

Contextual equivalence for higher-order #pi#-calculus revisited

Includes bibliographical references. Title from coverAvailable from British Library Document Supply Centre- DSC:7623. 6171(04/2002) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Contextual equivalence for higher-order pi-calculus revisited

The higher-order pi-calculus is an extension of the pi-calculus to allow communication of abstractions of processes rather than names alone. It has been studied intensively by Sangiorgi in his thesis where a characterisation of a contextual equivalence for higher-order pi-calculus is provided using labelled transition systems and normal bisimulations. Unfortunately the proof technique used there requires a restriction of the language to only allow finite types. We revisit this calculus and offer an alternative presentation of the labelled transition system and a novel proof technique which allows us to provide a fully abstract characterisation of contextual equivalence using labelled transitions and bisimulations for higher-order pi-calculus with recursive types also

Themen und weitere Hinweise für das Seminar

3.4 Subcalculi of the π-calculus........................... 6 3.5 Contextual equivalence for higher-order pi-calculus revisited......... 6 3.6 Typed π-Calculi................................. 7 3.7 The Join Calculus: A Language for Distributed Mobile Programming.... 7 3.8 May and Must Testing in the Join-Calculus..................