Formal ReSpecT

Logic-based languages have already proved to be effective to build individual agents and to enable inter-agent communication in multi-agent systems. Also, logic tuple centres have shown that logic-based languages can be effectively exploited to rule inter-agent communication so as to build social behaviours. In this paper, we formally define the notion of logic tuple centre as well as the operational semantics of the logic-based language ReSpecT for the behaviour specification of logic tuple centres. For this purpose, we exploit a formal framework for asynchronous systems allowing coordination media to be represented in a separate and independent way with respect to the coordinated entities. As a by-product, this shows that a logicbased approach may be effectively exploited for the coordination of heterogeneous agents of different sorts and technologies. 1 Coordination media for multi-agent systems Multi-agent systems are rapidly becoming a fundamental paradigm for the engineering of complex software systems in the Internet era [18,9,25]. Agents, agent societies, and agent environments are likely to be the basic abstractions around which systems of tomorrow will be built [22]. Broadly speaking, interaction is probably the most relevant feature of complex systems of today: systems are built by putting together sub-systems (like object, processes, components, agents) that interact so as to achieve a global system goal. In multi-agent systems, the issue of governing agent interaction is particularly relevant. In fact, agents are usually supposed to have a partial knowledge of their surrounding environment, as well as limited capabilities to affect its state, to perceive its modifications, and to understand and foresee its possible evolution. So, they typically depend on interaction with both other agents and the environment to fulfil their goals. Even more, when Internet agents are involved, the heterogeneity, dynamics, and unpredictability 1 Email:[email protected] 2 Email:[email protected] c ©2001 Published by Elsevier Science B. V.