Results 1  10
of
22
Deriving structural labelled transitions for mobile ambients
, 2008
"... Abstract. We present a new labelled transition system (lts) for the ambient calculus on which ordinary bisimilarity coincides with contextual equivalence. The key feature of this lts is that it is the fruit of ongoing work on developing a systematic procedure for deriving ltss in the structural styl ..."
Abstract

Cited by 20 (2 self)
 Add to MetaCart
(Show Context)
Abstract. We present a new labelled transition system (lts) for the ambient calculus on which ordinary bisimilarity coincides with contextual equivalence. The key feature of this lts is that it is the fruit of ongoing work on developing a systematic procedure for deriving ltss in the structural style from the underlying reduction semantics and observability. Notably, even though we have derived our lts for ambients systematically it compares very favourably with existing transition systems for the same calculus.
Deriving Labels and Bisimilarity for Concurrent Constraint Programming
, 2010
"... Abstract. Concurrent constraint programming (ccp) is a wellestablished model for concurrency that builds upon operational and algebraic notions from process calculi and firstorder logic. Bisimilarity is one of the central reasoning techniques in concurrency. The standard definition of bisimilarity ..."
Abstract

Cited by 12 (9 self)
 Add to MetaCart
(Show Context)
Abstract. Concurrent constraint programming (ccp) is a wellestablished model for concurrency that builds upon operational and algebraic notions from process calculi and firstorder logic. Bisimilarity is one of the central reasoning techniques in concurrency. The standard definition of bisimilarity, however, is not completely satisfactory for ccp since it yields an equivalence that is too fine grained. By building upon recent foundational investigations, we introduce a labelled w.r.t. the typical observational equivalence in ccp. This way we provide ccp with a new proof technique for ccp coherent with existing ones.
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 ( ..."
Abstract

Cited by 8 (1 self)
 Add to MetaCart
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.
A graph syntax for processes and services
 Proceedings of the 6th International Workshop on Web Services and Formal Methods (WSFM’09), volume 6194 of Lecture Notes in Computer Science
, 2010
"... Abstract. We propose a class of hierarchical graphs equipped with a simple algebraic syntax as a convenient way to describe the configurations of languages equipped with inherently hierarchical features such as sessions, faulthandling scopes, transactions or locations. The graph syntax can be seen ..."
Abstract

Cited by 8 (5 self)
 Add to MetaCart
(Show Context)
Abstract. We propose a class of hierarchical graphs equipped with a simple algebraic syntax as a convenient way to describe the configurations of languages equipped with inherently hierarchical features such as sessions, faulthandling scopes, transactions or locations. The graph syntax can be seen as an intermediate representation language, that facilitates the encoding of algebraic specifications and, in particular, of process calculi, since it provides primitives for nesting, name restriction and parallel composition. The syntax is based on an algebraic presentation of graphs that faithfully characterises families of hierarchical graphs, meaning that each term of the language identifies uniquely an equivalence class of graphs (modulo graph isomorphism). Proving soundness and correctness of an encoding with respect to graph isomorphism (i.e. proving that congruent processes are mapped to isomorphic graphs) is then facilitated and can be done by structural induction. Summing up, the graph syntax facilitates the definition of faithful encodings, yet allowing a precise visual representation. We instantiate our proposal by offering the graphical encoding of a workflow language and a serviceoriented calculus. 1
Coalgebraic Symbolic Semantics
"... The operational semantics of interactive systems is usually described by labeled transition systems. Abstract semantics (that is defined in terms of bisimilarity) is characterized by the final morphism in some category of coalgebras. Since the behaviour of interactive systems is for many reasons in ..."
Abstract

Cited by 5 (2 self)
 Add to MetaCart
(Show Context)
The operational semantics of interactive systems is usually described by labeled transition systems. Abstract semantics (that is defined in terms of bisimilarity) is characterized by the final morphism in some category of coalgebras. Since the behaviour of interactive systems is for many reasons infinite, symbolic semantics were introduced as a mean to define smaller, possibly finite, transition systems, by employing symbolic actions and avoiding some sources of infiniteness. Unfortunately, symbolic bisimilarity has a different “shape” with respect to ordinary bisimilarity, and thus the standard coalgebraic characterization does not work. In this paper, we introduce its coalgebraic models.
Characterizing contextual equivalence in calculi with passivation
 INFORMATION AND COMPUTATION
, 2011
"... ..."
On the Decidability Status of Reachability and Coverability in Graph Transformation Systems
, 2012
"... We study decidability issues for reachability problems in graph transformation systems, a powerful infinitestate model. For a fixed initial configuration, we consider reachability of an entirely specified configuration and of a configuration that satisfies a given pattern (coverability). The former ..."
Abstract

Cited by 4 (1 self)
 Add to MetaCart
We study decidability issues for reachability problems in graph transformation systems, a powerful infinitestate model. For a fixed initial configuration, we consider reachability of an entirely specified configuration and of a configuration that satisfies a given pattern (coverability). The former is a fundamental problem for any computational model, the latter is strictly related to verification of safety properties in which the pattern specifies an infinite set of bad configurations. In this paper we reformulate results obtained, e.g., for contextfree graph grammars and concurrency models, such as Petri nets, in the more general setting of graph transformation systems and study new results for classes of models obtained by adding constraints on the form of reduction rules.
Efficient Computation of Program Equivalence for Confluent Concurrent Constraint Programming∗
"... Concurrent Constraint Programming (ccp) is a wellestablished declarative framework from concurrency theory. Its foundations and principles e.g., semantics, proof systems, axiomatizations, have been thoroughly studied for over the last two decades. In contrast, the development of algorithms and auto ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
(Show Context)
Concurrent Constraint Programming (ccp) is a wellestablished declarative framework from concurrency theory. Its foundations and principles e.g., semantics, proof systems, axiomatizations, have been thoroughly studied for over the last two decades. In contrast, the development of algorithms and automatic verification procedures for ccp have hitherto been far too little considered. To the best of our knowledge there is only one existing verification algorithm for the standard notion of ccp program (observational) equivalence. In this paper we first show that this verification algorithm has an exponentialtime complexity even for programs from a representative sublanguage of ccp; the summationfree fragment (ccp{+}). We then significantly improve on the complexity of this algorithm by providing two alternative polynomialtime decision procedures for ccp{+} program equivalence. Each of these two procedures