Towards a Unified Framework for Declarative Structured Communications

We present a unified framework for the declarative analysis of structured communications. By relying on a (timed) concurrent constraint programming language, we show that in addition to the usual operational techniques from process calculi, the analysis of structured communications can elegantly exploit logic-based reasoning techniques. We introduce a declarative interpretation of the language for structured communications proposed by Honda, Vasconcelos, and Kubo. Distinguishing features of our approach are: the possibility of including partial information (constraints) in the session model; the use of explicit time for reasoning about session duration and expiration; a tight correspondence with logic, which formally relates session execution and linear-time temporal logic formulas

Concurrent Constraints in the Fusion Calculus (Extended Abstract)

We use the fusion calculus, a generalization and simplification of the ß-calculus, to model concurrent constraint programming. In particular we encode three basic variants of the ae-calculus, which is a foundational calculus for the concurrent constraint programming language Oz. Using a new reduction-based semantics and weak barbed congruences for the fusion calculus we formally establish an operational correspondence between the ae- calculi and their encodings. These barbed congruences are shown to coincide with the hyperequivalences previously adopted for the fusion calculus. 1 Introduction In this paper we use the fusion calculus to model concurrent constraint programming, thereby relating the paradigm of communicating processes to that of concurrent constraints. In the first, parallel agents interact with each other by sending and receiving data over named ports; in the second, agents produce constraints on the values of variables, which are combined to resolve queries about the ..