Power and dependence in multiagent systems

An important aim in the field of Multiagent Systems is to study emergent social structures, such as groups and collectives. The relevan ce of social structures in Distributed Artificial Intelligence [5, 6], Artificial Life [7], Sociology [3] necessitates a well motivated definition of their characteristics. The research question of this paper is to formalize the results obtained by Castelfranchi [3] that try to bridge the gap between the BDI model and the macro-level of Multiagent Systems. We presented in [2] general social viewpoints on Multiagent Systems and in [1] we have detailed a derivation of coalition structures from power structures. In this paper we continue the research, and we define power in terms of cognitive (or mind) view, i.e., starting from the characteristics of the single agents as their goals and skills. Properties of collectives, as mutual dependence or cooperation, are also hierarchically defined by means of the definition of power. It is shown that upper levels of this hierarchy need mental model of the agents more and more complex. In real systems some actions can obstruct or ruin the effects of some others, sometimes they simply cannot be performed at the same time, or one of them has the priority over the others. All these features are referred to as the concurrency management problem and w e formalize it in our system to improve its expressiveness.