Abstract
This contribution presents a knowledge-based model of the agents' mutual awareness (social knowledge) and justifies its role in various classes of applications of the concept of multi-agent systems. A tri-base acquaintance model (3bA) has been formalized and designed in order to limit explosive communication space in multi-agent systems. As a formal model of agent's social behaviour knowledge and agent's cooperation neighbourhood knowledge, the 3bA model approach provides MAS designers with knowledge structures and knowledge maintenance mechanism. Applications of the 3bA model to the following areas are commented: production planning, supply chain management, coalition formation and intrusion detection. The study concludes with a unifying view on social knowledge structuring.