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16
Acceptance Trees for Probabilistic Processes
 In CONCUR'95, LNCS 962
, 1995
"... . In this paper we study the extension of classical testing theory to a probabilistic process algebra. We consider a generative interpretation of probabilities for a language with two choice operators (one internal and the other external), which are annotated with a probability p 2 (0; 1). We defin ..."
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Cited by 19 (8 self)
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. In this paper we study the extension of classical testing theory to a probabilistic process algebra. We consider a generative interpretation of probabilities for a language with two choice operators (one internal and the other external), which are annotated with a probability p 2 (0; 1). We define a testing semantics for our language, and we write P passp T to denote that the process P passes the test T with a probability p. We also give a set of essential tests which has the same strength as the full family of tests. Next we give an alternative characterization of the testing semantics, based on the idea of acceptance sets, and we prove that the new equivalence is equal to the testing equivalence. Finally, we present a fully abstract denotational semantics based on acceptance trees. 1 Introduction During the last years there has been a great activity devoted to the study of time and probabilistic extensions of concurrent processes. These extensions are very adequate for the spe...
Equivalences on Observable Processes
 In Proceedings of the 7th Annual IEEE Symposium on Logic in Computer Science
, 1992
"... The aim of this paper is to nd the nest `observable ' and `implementable' equivalence on concurrent processes. This is a part of a larger programme to develop a theory of observable processes where semantics of processes are based on locally and nitely observable process behaviour, and all proce ..."
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Cited by 19 (6 self)
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The aim of this paper is to nd the nest `observable ' and `implementable' equivalence on concurrent processes. This is a part of a larger programme to develop a theory of observable processes where semantics of processes are based on locally and nitely observable process behaviour, and all process constructs are allowed, provided their operational meaning is de ned by realistically implementable transition rules.
Basic Observables for Processes
 Information and Computation
, 1999
"... A general approach for defining behavioural preorders over process terms as the maximal precongruences induced by basic observables is examined. Three different observables, that provide information about the initial communication capabilities of processes and about the possibility that processes ..."
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Cited by 16 (4 self)
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A general approach for defining behavioural preorders over process terms as the maximal precongruences induced by basic observables is examined. Three different observables, that provide information about the initial communication capabilities of processes and about the possibility that processes get engaged in divergent computations, will be considered. We show that the precongruences induced by our basic observables coincide with intuitive and/or widely studied behavioural preorders. In particular, we retrieve in our setting the must preorder of De Nicola and Hennessy and the fair/should preorder introduced by Cleaveland and Natarajan and by Brinksma, Rensink and Vogler. A new form of testing preorder, which we call safemust, also emerges. The alternative characterizations we offer shed light on the differences between these preorders, and on the role played in their definition by tests for divergence. 1 Introduction In the classical theory of functional programming, the point...
Actors, Actions, and Initiative in Normative System Specification
"... The logic of norms, called deontic logic, has been used to specify normative constraints for information systems. For example, one can specify in deontic logic the constraints that a book borrowed from a library should be returned within three weeks, and that if it is not returned, the library shoul ..."
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Cited by 13 (1 self)
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The logic of norms, called deontic logic, has been used to specify normative constraints for information systems. For example, one can specify in deontic logic the constraints that a book borrowed from a library should be returned within three weeks, and that if it is not returned, the library should send a reminder. Thus, the notion of obligation to perform an action arises naturally in system specification.
Axiomatisations of Weak Equivalences for De Simone Languages
 Proceedings of the 6th International Conference on Concurrency Theory CONCUR'95
, 1995
"... . Aceto, Bloom and Vaandrager proposed in [ABV92] a procedure for generating a complete axiomatisation of strong bisimulation for process languages in the GSOS format. However, the choice operator +, which the procedure uses, as well as other auxiliary GSOS operators, which it introduces to obtain a ..."
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Cited by 9 (2 self)
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. Aceto, Bloom and Vaandrager proposed in [ABV92] a procedure for generating a complete axiomatisation of strong bisimulation for process languages in the GSOS format. However, the choice operator +, which the procedure uses, as well as other auxiliary GSOS operators, which it introduces to obtain a finite axiomatisation, do not preserve many of weak equivalences. We propose a modification of this procedure, which works for a subclass of process languages in the De Simone format with a special treatment of silent actions. A choice of such a subclass of process languages guarantees that all the considered and auxiliary operators preserve many of weak equivalences. Our procedure generates a complete axiomatisation of refusal simulation preorder and it can be easily adapted to coarser preorders. The completeness result depends on the completeness result for the basic process language, which we prove. This language does not use prefixing with ø and the choice operator +. Instead, we employ...
Finite axiom systems for testing preorder and De Simone Process Languages
, 2000
"... We prove that testing preorder of De Nicola and Hennessy is preserved by all operators of De Simone process languages. Building upon this result we propose an algorithm for generating axiomatisations of testing preorder for arbitrary De Simone process languages. The axiom systems produced by our alg ..."
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Cited by 8 (2 self)
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We prove that testing preorder of De Nicola and Hennessy is preserved by all operators of De Simone process languages. Building upon this result we propose an algorithm for generating axiomatisations of testing preorder for arbitrary De Simone process languages. The axiom systems produced by our algorithm are finite and complete for processes with nite behaviour. In order to achieve completeness for a subclass of processes with infiite behaviour we use one infinitary induction rule. The usefulness of our results is illustrated in specification and verification of small concurrent systems, where suspension, resumption and alternation of execution of component systems occur. We argue that better speci cations can be written in customised De Simone process languages, which contain both the standard operators as well as new De Simone operators that are specifically tailored for the task in hand. Moreover, the automatically generated axiom systems for such specification languages make the verification more straightforward.
A Filter Model for Mobile Processes
 MATH. STRUCT. IN COMP. SCIENCE
, 1993
"... This paper presents a filter model for πcalculus, and shows its full abstraction with respect to a "may" operational semantics. The model is introduced in the form of a type assignment system. Types are related by a preorder which mimics the operational behaviour of terms. A subject expansion th ..."
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Cited by 7 (3 self)
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This paper presents a filter model for πcalculus, and shows its full abstraction with respect to a "may" operational semantics. The model is introduced in the form of a type assignment system. Types are related by a preorder which mimics the operational behaviour of terms. A subject expansion theorem holds. Terms are interpreted as filters of types: this interpretation is compositional. The proof of full abstraction relies on a notion of realizability of types, and on the construction of terms, which test when an arbitrary term has a fixed type.
A Hoarestyle Proof System for LOTOS
, 1991
"... A Hoarestyle proof system for LOTOS, defined in terms of proof rules based on the structure of processes, is presented. Hoare's satisfaction relation is used to define these rules. This system is based on the failures model. It is shown to be adequate to allow proofs of correctness of compound proc ..."
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Cited by 2 (0 self)
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A Hoarestyle proof system for LOTOS, defined in terms of proof rules based on the structure of processes, is presented. Hoare's satisfaction relation is used to define these rules. This system is based on the failures model. It is shown to be adequate to allow proofs of correctness of compound processes to be constructed from proofs of correctness of its parts. An example, consisting of the proof of a property of the failure set of a twoslot buffer is presented. 1 INTRODUCTION The established method for proving properties of LOTOS processes is bisimulation. This method, wellknown in process algebras (see among others [Par81, Mil80, Mil89]) has been extended to LOTOS in a number of papers [BC89], among which one of the most complete is the PhD thesis of Brinksma [Bri88a]. By using bisimulation, one can prove a LOTOS process equivalent to another LOTOS process. An example of this way of proceeding is presented in papers by [Naj87] and by Shiratori et al. [SKTN90], where service proce...
On the Operational Semantics of Nondeterminism and Divergence
, 1995
"... An operational model of nondeterministic processes coupled with a novel theory of divergence is presented. The operational model represents internal nondeterminism without using explicit internal transitions. Here the notion of internal state e#ectively replaces the familiar notion of internal trans ..."
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Cited by 2 (0 self)
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An operational model of nondeterministic processes coupled with a novel theory of divergence is presented. The operational model represents internal nondeterminism without using explicit internal transitions. Here the notion of internal state e#ectively replaces the familiar notion of internal transition, giving rise to an alternative operational view of processes: the weak process. Roughly, a weak process is a collection of stable internal states together with a set of transitions each of which is defined from an internal state to another weak process. Internal nondeterminism arises from such refinement of processes into multiple internal states. A simple extension to the basic weak process model gives rise to an elaborate operational theory of divergence. According to this theory, the ability of a process to undertake an infinite internal computation which is pathological, or persistent, is distinguished from its ability to undertake an infinite internal computation which is not. Alt...