17,472 research outputs found
Congruence from the Operator's Point of View: Compositionality Requirements on Process Semantics
One of the basic sanity properties of a behavioural semantics is that it
constitutes a congruence with respect to standard process operators. This issue
has been traditionally addressed by the development of rule formats for
transition system specifications that define process algebras. In this paper we
suggest a novel, orthogonal approach. Namely, we focus on a number of process
operators, and for each of them attempt to find the widest possible class of
congruences. To this end, we impose restrictions on sublanguages of
Hennessy-Milner logic, so that a semantics whose modal characterization
satisfies a given criterion is guaranteed to be a congruence with respect to
the operator in question. We investigate action prefix, alternative
composition, two restriction operators, and parallel composition.Comment: In Proceedings SOS 2010, arXiv:1008.190
Adequacy of compositional translations for observational semantics
We investigate methods and tools for analysing translations between programming languages with respect to observational semantics. The behaviour of programs is observed in terms of may- and must-convergence in arbitrary contexts, and adequacy of translations, i.e., the reflection of program equivalence, is taken to be the fundamental correctness condition. For compositional translations we propose a notion of convergence equivalence as a means for proving adequacy. This technique avoids explicit reasoning about contexts, and is able to deal with the subtle role of typing in implementations of language extension
A generic operational metatheory for algebraic effects
We provide a syntactic analysis of contextual preorder and equivalence for a polymorphic programming language with effects. Our approach applies uniformly across a range of algebraic effects, and incorporates, as instances: errors, input/output, global state, nondeterminism, probabilistic choice, and combinations thereof. Our approach is to extend Plotkin and Powerâs structural operational semantics for algebraic effects (FoSSaCS 2001) with a primitive âbasic preorderâ on ground type computation trees. The basic preorder is used to derive notions of contextual preorder and equivalence on program terms. Under mild assumptions on this relation, we prove fundamental properties of contextual preorder (hence equivalence) including extensionality properties and a characterisation via applicative contexts, and we provide machinery for reasoning about polymorphism using relational parametricity
Iterated learning and grounding: from holistic to compositional languages
This paper presents a new computational model for studying the origins and evolution of compositional languages grounded through the interaction between agents and their environment. The model is based on previous work on adaptive grounding of lexicons and the iterated learning model. Although the model is still in a developmental phase, the first results show that a compositional language can emerge in which the structure reflects regularities present in the population's environment
Event-internal modifiers : semantic underspecification and conceptual interpretation
The article offers evidence that there are two variants of adverbial modification that differ with respect to the way in which a modifier is linked to the verbs eventuality argument. So-called event-external modifiers relate to the full eventuality, whereas event-internal modifiers relate to some integral part of it. The choice between external and internal modification is shown to be dependent on the modifiers syntactic base position. Event-external modifiers are base-generated at the VP periphery, whereas event-internal modifiers are base-generated at the V periphery. These observations are accounted for by a refined version of the standard Davidsonian approach to adverbial modification according to which modification is mediated by a free variable. In the case of external modification, the grammar takes responsibility for identifying the free variable with the verbs eventuality argument, whereas in the case of internal modification, a value for the free variable is determined by the conceptual system on the basis of contextually salient world knowledge. For the intriguing problem that certain locative modifiers occasionally seem to have nonlocative (instrumental, positional, or manner) readings, the advocated approach can provide a rather simple solution
An interactive semantics of logic programming
We apply to logic programming some recently emerging ideas from the field of
reduction-based communicating systems, with the aim of giving evidence of the
hidden interactions and the coordination mechanisms that rule the operational
machinery of such a programming paradigm. The semantic framework we have chosen
for presenting our results is tile logic, which has the advantage of allowing a
uniform treatment of goals and observations and of applying abstract
categorical tools for proving the results. As main contributions, we mention
the finitary presentation of abstract unification, and a concurrent and
coordinated abstract semantics consistent with the most common semantics of
logic programming. Moreover, the compositionality of the tile semantics is
guaranteed by standard results, as it reduces to check that the tile systems
associated to logic programs enjoy the tile decomposition property. An
extension of the approach for handling constraint systems is also discussed.Comment: 42 pages, 24 figure, 3 tables, to appear in the CUP journal of Theory
and Practice of Logic Programmin
Models for CSP with availability information
We consider models of CSP based on recording what events are available as
possible alternatives to the events that are actually performed. We present
many different varieties of such models. For each, we give a compositional
semantics, congruent to the operational semantics, and prove full abstraction
and no-junk results. We compare the expressiveness of the different models.Comment: In Proceedings EXPRESS'10, arXiv:1011.601
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