1,034 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
On the axiomatizability of impossible futures
A general method is established to derive a ground-complete axiomatization for a weak semantics from such an axiomatization for its concrete counterpart, in the context of the process algebra BCCS. This transformation moreover preserves omega-completeness. It is applicable to semantics at least as coarse as impossible futures semantics. As an application, ground- and omega-complete axiomatizations are derived for weak failures, completed trace and trace semantics. We then present a finite, sound, ground-complete axiomatization for the concrete impossible futures preorder, which implies a finite, sound, ground-complete axiomatization for the weak impossible futures preorder. In contrast, we prove that no finite, sound axiomatization for BCCS modulo concrete and weak impossible futures equivalence is ground-complete. If the alphabet of actions is infinite, then the aforementioned ground-complete axiomatizations are shown to be omega-complete. If the alphabet is finite, we prove that the inequational theories of BCCS modulo the concrete and weak impossible futures preorder lack such a finite basis
Equational Characterization of Covariant-Contravariant Simulation and Conformance Simulation Semantics
Covariant-contravariant simulation and conformance simulation generalize
plain simulation and try to capture the fact that it is not always the case
that "the larger the number of behaviors, the better". We have previously
studied their logical characterizations and in this paper we present the
axiomatizations of the preorders defined by the new simulation relations and
their induced equivalences. The interest of our results lies in the fact that
the axiomatizations help us to know the new simulations better, understanding
in particular the role of the contravariant characteristics and their interplay
with the covariant ones; moreover, the axiomatizations provide us with a
powerful tool to (algebraically) prove results of the corresponding semantics.
But we also consider our results interesting from a metatheoretical point of
view: the fact that the covariant-contravariant simulation equivalence is
indeed ground axiomatizable when there is no action that exhibits both a
covariant and a contravariant behaviour, but becomes non-axiomatizable whenever
we have together actions of that kind and either covariant or contravariant
actions, offers us a new subtle example of the narrow border separating
axiomatizable and non-axiomatizable semantics. We expect that by studying these
examples we will be able to develop a general theory separating axiomatizable
and non-axiomatizable semantics.Comment: In Proceedings SOS 2010, arXiv:1008.190
On the Existence of a Finite Base for Complete Trace Equivalence over BPA with Interrupt
We study Basic Process Algebra with interrupt modulo complete trace equivalence. We show that, unlike in the setting of the more demanding bisimilarity, a ground complete finite axiomatization exists. We explicitly give such an axiomatization, and extend it to a finite complete one in the special case when a single action is present
Turing Automata and Graph Machines
Indexed monoidal algebras are introduced as an equivalent structure for
self-dual compact closed categories, and a coherence theorem is proved for the
category of such algebras. Turing automata and Turing graph machines are
defined by generalizing the classical Turing machine concept, so that the
collection of such machines becomes an indexed monoidal algebra. On the analogy
of the von Neumann data-flow computer architecture, Turing graph machines are
proposed as potentially reversible low-level universal computational devices,
and a truly reversible molecular size hardware model is presented as an
example
Extensions of Standard Weak Bisimulation Machinery: Finite-state General Processes, Refinable Actions, Maximal-progress and Time
AbstractWe present our work on extending the standard machinery for weak bisimulation to deal with: finite-state processes of calculi with a full signature, including static operators like parallel; semantic action refinement and ST bisimulation; maximal-progress, i.e. priority of standard actions over unprioritized actions; representation of time: discrete real-time and Markovian stochastic time. For every such topic we show that it is possible to resort simply to weak bisimulation and that we can exploit this to obtain, via modifications to the standard machinery: finite-stateness of semantic models when static operators are not replicable by recursion, as for CCS with the standard semantics, thus yielding decidability of equivalence; structural operational semantics for terms; a complete axiomatization for finite-state processes via a modification of the standard theory of standard equation sets and of the normal-form derivation procedure
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