404 research outputs found
A confluent calculus for concurrent constraint programming with guarded choice
. Confluence is an important and desirable property as it allows the program to be understood by considering any desired scheduling rule, rather than having to consider all possible schedulings. Unfortunately, the usual operational semantics for concurrent constraint programs is not confluent as different process schedulings give rise to different sets of possible outcomes. We show that it is possible to give a natural confluent calculus for concurrent constraint programs, if the syntactic domain is extended by a blind choice operator and a special constant standing for a discarded branch. This has application to program analysis. 1 Introduction Concurrent constraint programming (ccp) [16, 15] is a recent programmingparadigm which elegantly combines logical concepts and concurrency mechanisms. The computational model of ccp is based on the notion of a constraint system, which consists of a set of constraints and an entailment relation. Processes interact through a common store. Commun..
Connectors meet Choreographies
We present Cho-Reo-graphies (CR), a new language model that unites two
powerful programming paradigms for concurrent software based on communicating
processes: Choreographic Programming and Exogenous Coordination. In CR,
programmers specify the desired communications among processes using a
choreography, and define how communications should be concretely animated by
connectors given as constraint automata (e.g., synchronous barriers and
asynchronous multi-casts). CR is the first choreography calculus where
different communication semantics (determined by connectors) can be freely
mixed; since connectors are user-defined, CR also supports many communication
semantics that were previously unavailable for choreographies. We develop a
static analysis that guarantees that a choreography in CR and its user-defined
connectors are compatible, define a compiler from choreographies to a process
calculus based on connectors, and prove that compatibility guarantees
deadlock-freedom of the compiled process implementations
Linear-Logic Based Analysis of Constraint Handling Rules with Disjunction
Constraint Handling Rules (CHR) is a declarative committed-choice programming
language with a strong relationship to linear logic. Its generalization CHR
with Disjunction (CHRv) is a multi-paradigm declarative programming language
that allows the embedding of horn programs. We analyse the assets and the
limitations of the classical declarative semantics of CHR before we motivate
and develop a linear-logic declarative semantics for CHR and CHRv. We show how
to apply the linear-logic semantics to decide program properties and to prove
operational equivalence of CHRv programs across the boundaries of language
paradigms
Observational equivalences for linear logic CC languages
Linear logic Concurrent Constraint programming (LCC) is an extension of
concurrent constraint programming (CC) where the constraint system is based on
Girard's linear logic instead of the classical logic. In this paper we address
the problem of program equivalence for this programming framework. For this
purpose, we present a structural operational semantics for LCC based on a label
transition system and investigate different notions of observational
equivalences inspired by the state of art of process algebras. Then, we
demonstrate that the asynchronous \pi-calculus can be viewed as simple
syntactical restrictions of LCC. Finally we show LCC observational equivalences
can be transposed straightforwardly to classical Concurrent Constraint
languages and Constraint Handling Rules, and investigate the resulting
equivalences.Comment: 17 page
Variations on a Theme: A Bibliography on Approaches to Theorem Proving Inspired From Satchmo
This articles is a structured bibliography on theorem provers,
approaches to theorem proving, and theorem proving applications inspired
from Satchmo, the model generation theorem prover developed
in the mid 80es of the 20th century at ECRC, the European Computer-
Industry Research Centre. Note that the bibliography given in this article
is not exhaustive
On Asynchronous Session Semantics
This paper studies a behavioural theory of the π-calculus with session types under the fundamental principles of the practice of distributed computing — asynchronous communication which is order-preserving inside each connection (session), augmented with asynchronous inspection of events (message arrivals). A new theory of bisimulations is introduced, distinct from either standard
asynchronous or synchronous bisimilarity, accurately capturing the semantic nature of session-based asynchronously communicating processes augmented with
event primitives. The bisimilarity coincides with the reduction-closed barbed congruence. We examine its properties and compare them with existing semantics.
Using the behavioural theory, we verify that the program transformation of multithreaded into event-driven session based processes, using Lauer-Needham duality,
is type and semantic preserving
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