Multiagent systems and societies of agents

Agents operate and exist in some environment, which typically is both computational and physical. The environment might be open or closed, and it might or might not contain other agents. Although there are situations where an agent can operate usefully by itself, the increasing interconnection and networking of computers is making such situations rare, and in the usual state of aaairs the agent interacts with other agents. Whereas the previous chapter deened the structure and characteristics of an individual agent, the focus of this chapter is on systems with multiple agents. At times, the number of agents may be too numerous to deal with them individually, and it is then more convenient to deal with them collectively, as a society of agents. In this chapter, we will learn how to analyze, describe, and design environments in which agents can operate eeectively and interact with each other productively. The environments will provide a computational infrastructure for such interactions to take place. The infrastructure will include protocols for agents to communicate and protocols for agents to interact. Communication protocols enable agents to exchange and understand messages. Interaction protocols enable agents to have conversations, which for our purposes are structured exchanges of messages. As a concrete example of these, a communication protocol might specify that the following types of messages can be exchanged between two agents: Propose a course of action Accept a course of action Reject a course of action Retract a course of action Disagree with a proposed course of action Counterpropose a course of action Based on these message types, the following conversation|an instance of an