31 research outputs found
Meta SOS - A Maude Based SOS Meta-Theory Framework
Meta SOS is a software framework designed to integrate the results from the
meta-theory of structural operational semantics (SOS). These results include
deriving semantic properties of language constructs just by syntactically
analyzing their rule-based definition, as well as automatically deriving sound
and ground-complete axiomatizations for languages, when considering a notion of
behavioural equivalence. This paper describes the Meta SOS framework by
blending aspects from the meta-theory of SOS, details on their implementation
in Maude, and running examples.Comment: In Proceedings EXPRESS/SOS 2013, arXiv:1307.690
Weak Sequential Composition in Process Algebras
n this paper we study a special operator for sequential composition, which is defined relative to a dependency relation over the actions of a given system. The idea is that actions which are not dependent (intuitively because they share no common resources) do not have to wait for one another to proceed, even if they are composed sequentially. Such a notion has been studied before in a linear-time setting, but until recently there has been no systematic investigation in the context of process algebras.
We give a structural operational semantics for a process algebraic language containing such a sequential composition operator, which shows some interesting interplay with choice. We give a complete axiomatisation of strong bisimilarity and we show consistency of the operational semantics with an event-based denotational semantics developed recently by the second author. The axiom system allows to derive the communication closed layers law, which in the linear time setting has been shown to be a very useful instrument in correctness preserving transformations. We conclude with a couple of examples
Operational Semantics of Process Monitors
CSPe is a specification language for runtime monitors that can directly
express concurrency in a bottom-up manner that composes the system from
simpler, interacting components. It includes constructs to explicitly flag
failures to the monitor, which unlike deadlocks and livelocks in conventional
process algebras, propagate globally and aborts the whole system's execution.
Although CSPe has a trace semantics along with an implementation demonstrating
acceptable performance, it lacks an operational semantics. An operational
semantics is not only more accessible than trace semantics but also
indispensable for ensuring the correctness of the implementation. Furthermore,
a process algebra like CSPe admits multiple denotational semantics appropriate
for different purposes, and an operational semantics is the basis for
justifying such semantics' integrity and relevance. In this paper, we develop
an SOS-style operational semantics for CSPe, which properly accounts for
explicit failures and will serve as a basis for further study of its
properties, its optimization, and its use in runtime verification
CPO Models for GSOS Languages - Part I: Compact GSOS Languages
In this paper, we present a general way of giving denotational semantics to a class of languages equipped with an operational semantics that fits the GSOS format of Bloom, Istrail and Meyer. The canonical model used for this purpose will be Abramsky's domain of synchronization trees, and the denotational semantics automatically generated by our methods will be guaranteed to be fully abstract with respect to the finitely observable part of the bisimulation preorder. In the process of establishing the full abstraction result, we also obtain several general results on the bisimulation preorder (including a complete axiomatization for it), and give a novel operational interpretation of GSOS languages
Delayed choice for process algebra with abstraction
The delayed choice is an operator which serves to combine linear time and branching time within one process algebra. We study this operator in a theory with abstraction, more precisely, in a setting considering branching bisimulation. We show its use in scenario specifications and in verification to reduce irrelevant branching structure of a process
A general conservative extension theorem in process algebras with inequalities
We prove a general conservative extension theorem for transition system based process theories with easy-to-check and reasonable conditions. The core of this result is another general theorem which gives sufficient conditions for a system of operational rules and an extension of it in order to ensure conservativity, that is, provable transitions from an original term in the extension are the same as in the original system. As a simple corollary of the conservative extension theorem we prove a completeness theorem. We also prove a general theorem giving sufficient conditions to reduce the question of ground confluence modulo some equations for a large term rewriting system associated with an equational process theory to a small term rewriting system under the condition that the large system is a conservative extension of the small one. We provide many applications to show that our results are useful. The applications include (but are not limited to) various real and discrete time settings in ACP, ATP, and CCS and the notions projection, renaming, stage operator, priority, recursion, the silent step, autonomous actions, the empty process, divergence, etc