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A Conservative Look at Operational Semantics with Variable Binding
 INFORMATION AND COMPUTATION
, 1998
"... We set up a formal framework to describe transition system specifications in the style of Plotkin. This framework has the power to express manysortedness, general binding mechanisms and substitutions, among other notions such as negative hypotheses and unary predicates on terms. The framework i ..."
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Cited by 33 (4 self)
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We set up a formal framework to describe transition system specifications in the style of Plotkin. This framework has the power to express manysortedness, general binding mechanisms and substitutions, among other notions such as negative hypotheses and unary predicates on terms. The framework is used to present a conservativity format in operational semantics, which states sufficient criteria to ensure that the extension of a transition system specification with new transition rules does not affect the semantics of the original terms.
Bisimilarity of Open Terms
, 2000
"... Traditionally, in process calculi, relations over open terms, i.e., terms with free process variables, are defined as extensions of closedterm relations: two open terms are related if and only if all their closed instantiations are related. Working in the context of bisimulation, in this paper we s ..."
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Cited by 22 (0 self)
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Traditionally, in process calculi, relations over open terms, i.e., terms with free process variables, are defined as extensions of closedterm relations: two open terms are related if and only if all their closed instantiations are related. Working in the context of bisimulation, in this paper we study a different approach; we define semantic models for open terms, socalled conditional transition systems, and define bisimulation directly on those models. It turns out that this can be done in at least two different ways, one giving rise to De Simone's formal hypothesis bisimilarity and the other to a variation which we call hypothesispreserving bisimilarity (denoted t fh and t hp, respectively). For open terms, we have (strict) inclusions t fh /t hp / t ci (the latter denoting the standard ``closed instance' ' extension); for closed terms, the three coincide. Each of these relations is a congruence in the usual sense. We also give an alternative characterisation of t hp in terms of nonconditional transitions, as substitutionclosed bisimilarity (denoted t sb). Finally, we study the issue of recursion congruence: we prove that each of the above relations is a congruence with respect to the recursion operator; however, for t ci this result holds under more restrictive conditions than for tfh and thp.]
Rooted branching bisimulation as a congruence
 Journal of Computer and System Sciences
, 2000
"... This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, an ..."
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Cited by 17 (6 self)
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This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, and negative premises. 1
SOS formats and metatheory: 20 years after
, 2007
"... In 1981 Structural Operational Semantics (SOS) was introduced as a systematic way to define operational semantics of programming languages by a set of rules of a certain shape [G.D. Plotkin, A structural approach to operational semantics, Technical ..."
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Cited by 14 (5 self)
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In 1981 Structural Operational Semantics (SOS) was introduced as a systematic way to define operational semantics of programming languages by a set of rules of a certain shape [G.D. Plotkin, A structural approach to operational semantics, Technical
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 10 (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.
Ordered SOS Process Languages for Branching and Eager Bisimulations
 INFORMATION AND COMPUTATION
, 2002
"... We present a general and uniform method for defining structural operational semantics (SOS) of process operators by traditional Plotkinstyle transition rules equipped with orderings. This new feature allows one to control the order of application of rules when deriving transitions of process terms. ..."
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Cited by 4 (0 self)
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We present a general and uniform method for defining structural operational semantics (SOS) of process operators by traditional Plotkinstyle transition rules equipped with orderings. This new feature allows one to control the order of application of rules when deriving transitions of process terms. Our method is powerful enough to deal with rules with negative premises and copying. We show that rules with orderings, called ordered SOS rules, have the same expressive power as GSOS rules. We identify several classes of process languages with operators defined by rules with and without orderings in the setting with silent actions and divergence. We prove that branching bisimulation and eager bisimulation relations are preserved by all operators in process languages in the relevant classes.
A format for semantic equivalence comparison
, 2003
"... This paper presents a new format for process algebras, the extended tyft/tyxt format which generalises the tyft/tyxt format of Groote and Vaandrager. The format di ers from most previous formats in that the labels on transitions are treated as manysorted terms. Bisimulation is a congruence for all ..."
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Cited by 2 (0 self)
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This paper presents a new format for process algebras, the extended tyft/tyxt format which generalises the tyft/tyxt format of Groote and Vaandrager. The format di ers from most previous formats in that the labels on transitions are treated as manysorted terms. Bisimulation is a congruence for all operators de ned by extended transition system speci cations in this format. When one extended transition system speci cation is summed with another, the resulting bisimulation can either identify more terms (an abstracting extension up to bisimulation) or fewer terms (a re ning extension up to bisimulation) than the original bisimulation on the individual system. The notions of abstracting extension and re ning extension are de ned, and two theorems are presented giving conditions required for achieving each type of extension. These results provide a way to compare di erent semantic equivalences de ned for di erent process algebras. Finally, an application of this theory to semantic equivalence comparison is given for a new result relating Castellani’s pomset equivalence and Krishnan’s multiprocessor equivalence.
Structural congruences and structural operational semantics
, 2004
"... Structural congruences have been used to define the semantics and to capture inherent properties of language constructs. They have been used as an addendum to transition system specifications in Plotkin’s style of Structural Operational Semantics (SOS). However, there has been little theoretical wor ..."
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Cited by 1 (1 self)
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Structural congruences have been used to define the semantics and to capture inherent properties of language constructs. They have been used as an addendum to transition system specifications in Plotkin’s style of Structural Operational Semantics (SOS). However, there has been little theoretical work on establishing a formal link between theses two semantic specification frameworks. In this paper, we try to fill this gap by accommodating structural congruences inside transition system specifications. The Contributions of this paper can be summarized as follows: 1. Three interpretations of structural congruences in the SOS framework are presented; 2. The three interpretations are compared formally; 3. Syntactic criteria of a congruence format for structural congruences are given and proved correct; 4. Welldefinedness criteria for transition system specifications with negative premises are extended to the setting with structural congruences; 5. Operational and equational conservative extensions of languages with structural congruences are studied.