Soft Concurrent Constraint Programming

TL;DR

This paper introduces soft concurrent constraint programming (scc), a novel framework that integrates soft constraints into concurrent programming, enabling flexible, preference-based problem solving and negotiation among web agents.

Contribution

It extends classical concurrent constraint programming with soft constraints, allowing for preference handling and improved negotiation capabilities in distributed systems.

Findings

scc enables flexible preference expression in concurrent programming

The framework supports negotiation among web agents with incompatible requests

Soft constraints improve solution search efficiency in distributed scenarios

Abstract

Soft constraints extend classical constraints to represent multiple consistency levels, and thus provide a way to express preferences, fuzziness, and uncertainty. While there are many soft constraint solving formalisms, even distributed ones, by now there seems to be no concurrent programming framework where soft constraints can be handled. In this paper we show how the classical concurrent constraint (cc) programming framework can work with soft constraints, and we also propose an extension of cc languages which can use soft constraints to prune and direct the search for a solution. We believe that this new programming paradigm, called soft cc (scc), can be also very useful in many web-related scenarios. In fact, the language level allows web agents to express their interaction and negotiation protocols, and also to post their requests in terms of preferences, and the underlying soft constraint solver can find an agreement among the agents even if their requests are incompatible.