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Process Bisimulation via a Graphical Encoding
 IN: ICGT ‘06. VOLUME 4178 OF LNCS
, 2006
"... The paper presents a case study on the synthesis of labelled transition systems (ltss) for process calculi, choosing as testbed Milner’s Calculus of Communicating System (ccs). The proposal is based on a graphical encoding: each ccs process is mapped into a graph equipped with suitable interfaces, s ..."
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Cited by 20 (12 self)
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The paper presents a case study on the synthesis of labelled transition systems (ltss) for process calculi, choosing as testbed Milner’s Calculus of Communicating System (ccs). The proposal is based on a graphical encoding: each ccs process is mapped into a graph equipped with suitable interfaces, such that the denotation is fully abstract with respect to the usual structural congruence. Graphs with interfaces are amenable to the synthesis mechanism based on borrowed contexts (bcs), proposed by Ehrig and König (which are an instance of relative pushouts, originally introduced by Milner and Leifer). The bc mechanism allows the effective construction of an lts that has graphs with interfaces as both states and labels, and such that the associated bisimilarity is automatically a congruence. Our paper focuses on the analysis of the lts distilled by exploiting the encoding of ccs processes: besides offering some technical contributions towards the simplification of the bc mechanism, the key result of our work is the proof that the bisimilarity on processes obtained via bcs coincides with the standard strong bisimilarity for ccs.
Abstract Semantics by Observable Contexts
, 2008
"... The operational behavior of interactive systems is usually given in terms of transition systems labeled with actions, which, when visible, represent both observations and interactions with the external world. The abstract semantics is given in terms of behavioral equivalences, which depend on the ac ..."
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Cited by 10 (4 self)
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The operational behavior of interactive systems is usually given in terms of transition systems labeled with actions, which, when visible, represent both observations and interactions with the external world. The abstract semantics is given in terms of behavioral equivalences, which depend on the action labels and on the amount of branching structure considered. Behavioural equivalences are often congruences with respect to the operations of the language, and this property expresses the compositionality of the abstract semantics. A simpler approach, inspired by classical formalisms like λcalculus, Petri nets, term and graph rewriting, and pioneered by the Chemical Abstract Machine [1], defines operational semantics by means of structural axioms and reaction rules. Process calculi representing complex systems, in particular those able to generate and communicate names, are often defined in this way, since structural axioms give a clear idea of the intended structure of the states while reaction rules, which are often nonconditional, give a direct account of the possible steps. Transitions caused by reaction rules, however, are not labeled, since
Adhesive dpo parallelism for monic matches
 In Graph Transformation for Verification and Concurrency, GTVC2006
"... This paper presents indispensable technical results of a general theory that will allow to systematically derive from a given reduction system a behavioral congruence that respects concurrency. The theory is developed in the setting of adhesive categories and is based on the work by Ehrig and König ..."
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Cited by 2 (1 self)
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This paper presents indispensable technical results of a general theory that will allow to systematically derive from a given reduction system a behavioral congruence that respects concurrency. The theory is developed in the setting of adhesive categories and is based on the work by Ehrig and König on borrowed contexts; the latter are an instance of relative pushouts, which have been proposed by Leifer and Milner. In order to lift the concurrency theory of dpo rewriting to borrowed contexts we will study the special case of dpo rewriting with monic matches in adhesive categories: more specifically we provide a generalized Butterfly Lemma together with a Local Church Rosser and Parallelism theorem.
Finitely Branching Labelled Transition Systems from Reaction Semantics for Process Calculi
"... We investigate LeiferMilner RPO approach for CCS and π ..."
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We investigate LeiferMilner RPO approach for CCS and π
RPO, Secondorder Contexts, and λcalculus
"... We apply LeiferMilner RPO approach to the λcalculus, endowed with lazy and call by value reduction strategies. We show that, contrary to process calculi, one can deal directly with the λcalculus syntax and apply LeiferMilner technique to a category of contexts, provided that we work in the frame ..."
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Cited by 1 (0 self)
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We apply LeiferMilner RPO approach to the λcalculus, endowed with lazy and call by value reduction strategies. We show that, contrary to process calculi, one can deal directly with the λcalculus syntax and apply LeiferMilner technique to a category of contexts, provided that we work in the framework of weak bisimilarities. However, even in the case of the transition system with minimal contexts, the resulting bisimilarity is infinitely branching, due to the fact that, in standard context categories, parametric rules such as β can be represented only by infinitely many ground rules. To overcome this problem, we introduce the
Efficient Bisimilarities from Secondorder Reaction Semantics for πcalculus
, 2010
"... We investigate Leifer and Milner RPO approach for deriving efficient (finitely branching) LTS’s and bisimilarities for πcalculus. To this aim, we work in a category of secondorder term contexts and we apply a general pruning technique, which allows to simplify the set of transitions in the LTS obt ..."
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We investigate Leifer and Milner RPO approach for deriving efficient (finitely branching) LTS’s and bisimilarities for πcalculus. To this aim, we work in a category of secondorder term contexts and we apply a general pruning technique, which allows to simplify the set of transitions in the LTS obtained from the original RPO approach. The resulting LTS and bisimilarity provide an alternative presentation of symbolic LTS and Sangiorgi’s open bisimilarity.
Under consideration for publication in Math. Struct. in Comp. Science Concurrency Can’t Be Observed, Asynchronously †
, 2012
"... The paper is devoted to an analysis of the concurrent features of asynchronous systems. A preliminary step is represented by the introduction of a noninterleaving extension of barbed equivalence. This notion is then exploited in order to prove that concurrency cannot be observed through asynchronou ..."
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The paper is devoted to an analysis of the concurrent features of asynchronous systems. A preliminary step is represented by the introduction of a noninterleaving extension of barbed equivalence. This notion is then exploited in order to prove that concurrency cannot be observed through asynchronous interactions, i.e., that the interleaving and concurrent versions of a suitable asynchronous weak equivalence actually coincide. The theory is validated on some case studies, related to nominal calculi (πcalculus) and visual specification formalisms (Petri nets). Additionally, we prove that a class of systems which are (outputbuffered) asynchronous according to a characterisation previously proposed in the literature falls into our theory.
Efficient Bisimilarities from Secondorder Reaction Semantics for picalculus?
"... Abstract. We investigate Leifer and Milner RPO approach for deriving efficient (finitely branching) LTS’s and bisimilarities for picalculus. To this aim, we work in a category of secondorder term contexts and we apply a general pruning technique, which allows to simplify the set of transitions in ..."
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Abstract. We investigate Leifer and Milner RPO approach for deriving efficient (finitely branching) LTS’s and bisimilarities for picalculus. To this aim, we work in a category of secondorder term contexts and we apply a general pruning technique, which allows to simplify the set of transitions in the LTS obtained from the original RPO approach. The resulting LTS and bisimilarity provide an alternative presentation of symbolic LTS and Sangiorgi’s open bisimilarity.
RPO, Secondorder Contexts, and λcalculus?
"... Abstract. We apply LeiferMilner RPO approach to the λcalculus, endowed with lazy and call by value reduction strategies. We show that, contrary to process calculi, one can deal directly with the λcalculus syntax and apply LeiferMilner technique to a category of contexts, provided that we work ..."
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Abstract. We apply LeiferMilner RPO approach to the λcalculus, endowed with lazy and call by value reduction strategies. We show that, contrary to process calculi, one can deal directly with the λcalculus syntax and apply LeiferMilner technique to a category of contexts, provided that we work in the framework of weak bisimilarities. However, even in the case of the transition system with minimal contexts, the resulting bisimilarity is infinitely branching, due to the fact that, in standard context categories, parametric rules such as β can be represented only by infinitely many ground rules. To overcome this problem, we introduce the general notion of secondorder context category. We show that, by carrying out the RPO construction in this setting, the lazy (call by value) observational equivalence can be captured as a weak bisimilarity equivalence on a finitely branching transition system. This result is achieved by considering an encoding of λcalculus in Combinatory Logic. 1