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

Axiomatizations from Structural Operational Semantics: Theory and Tools

Structural Operational Semantics (SOS) is a well known standard for specifying language semantics in a natural, yet rigorous way. Once a formal way of checking for the equivalence of two programs written in such a language is provided, it is of great interest to derive efficient automated methods to prove if equivalences hold. Also of high interest for language designers is the possibility of enhancing the expressiveness of SOS in a formal manner, preserving as much from the already developed meta-theory of SOS as possible. The thesis focuses on these two areas, both from a theoretical and a practical perspective. The line of research addresses the extension of SOS with predicates and data, while lifting certain results from the meta-theory of SOS to these extensions. These results include automatically deriving axiomatizations for reasoning on program equivalence, and checking for compliance to rule formats in order to guarantee desired properties. Besides these extensions, the thesis provides an axiomatization for the coordination language Linda, presents a method to optimize axiomatizations for language constructs that are commutative, and presents a rule format for idempotent unary operators and idempotent terms. The practical aspect of this thesis consists of a core software framework for working with SOS meta-theories, named MetaSOS, which is implemented in Maude. The framework includes components for automatically deriving axiomatizations, performing simulations, and checking whether language constructs comply to a format for commutativity. It is designed in a modular and extensible fashion, and serves as a base for future implementations of other results from the meta-theory of SOS.Þegar þróa á áreiðanlegan og stöðugan hugbúnaðar er oft fyrsta skerfið að lýsa á formlegan hátt hvað skilyrðum hann á að uppfylla. Þetta er gert með því að búa til formleg líkön af hugbúnaðinum sem nota má í þesum tilgangi . Það hefur verið vinsælt á síðari árum að nota líkön sem byggja a svokallaða uppbyggingarvinnslumerkingafræði, (á ensku "structural operational semantics en oftast vitnað til sem SOS) sem er fomlegur fræðilegur rammi (e. meta theory) til að lýsa eiginleikum formlega málsins sem kerfinu er lýst í. Á síðastliðnum árum hafa miklar rannsóknuir verið stundaðar og gera niðurstöður þeirra það mögulegt að segja til um eiginleika formlegra mála með því að líta á reglurnar sem lýsa merkingarfræði þeirra. I þessu doktorverkefni leggur höfundur sitt af mörkum til SOS fræðanna frá tveimur sjónarmiðum. Annars vegar hefur hann útvíkkað almennu fræðin með því að bæta við mikilvægum hugtökum sem ekki hefur verið fjallað um áður. Hins vegar hefur hann forritað kerfi, byggt á almennu fræðunum, þar sem hægt er að spyrja spurninga um ákveðin tilvik og fá svör við þeim. Þetta kerfi hefur fengið góðar undirtektir hjá væntanlegum notendum og er mikilvægt skref í áttina að nýtingu á rannsóknaniðurstöðum í greininni.The work in this thesis was partially supported by the projects `Meta-theory of Algebraic Process Theories' (nr.~100014021) and `Extending and Axiomatizing Structural Operational Semantics: Theory and Tools' (nr.~1102940061) of the Icelandic Research Fund

Axiomatizing GSOS with Predicates

In this paper, we introduce an extension of the GSOS rule format with predicates such as termination, convergence and divergence. For this format we generalize the technique proposed by Aceto, Bloom and Vaandrager for the automatic generation of ground-complete axiomatizations of bisimilarity over GSOS systems. Our procedure is implemented in a tool that receives SOS specifications as input and derives the corresponding axiomatizations automatically. This paves the way to checking strong bisimilarity over process terms by means of theorem-proving techniques

PREG Axiomatizer : A Ground Bisimilarity Checker for GSOS with Predicates

PREG Axiomatizer is a tool used for proving strong bisimilarity between ground terms consisting of operations in the GSOS format extended with predicates. It automatically derives sound and ground-complete axiomatizations using a technique proposed by the authors of this paper. These axiomatizations are provided as input to the Maude system, which, in turn, is used as a reduction engine for provided ground terms. These terms are bisimilar if and only if their normal forms obtained in this fashion are equal. The motivation of this tool is the optimized handling of equivalence checking between complex ground terms within automated provers and checkers.publishe

Patterns for Maude Metalanguage Applications

One of the most effective ways of improving the quality of software engineering, system design and development, and communication between the people concerned with these problems, is provided by software patterns. In this paper we present a set of basic patterns for Maude metalanguage applications. We show the viability of the defined patterns by comparing them to the developing approaches for several well-known Maude tools.publishe