Negotiation in multi-agent systems

In systems composed of multiple autonomous agents, negotiation is a key form of interaction that enables groups of agents to arrive at a mutual agreement regarding some belief, goal or plan, for example. Particularly because the agents are autonomous and cannot be assumed to be benevolent, agents must influence others to convince them to act in certain ways, and negotiation is thus critical for managing such inter-agent dependencies. The process of negotiation may be of many different forms, such as auctions, protocols in the style of the contract net, and argumentation, but it is unclear just how sophisticated the agents or the protocols for interaction must be for successful negotiation in different contexts. All these issues were raised in the panel session on negotiation. As a prelude to the discussion, Jennings identified three broad topics for research on negotiation, that serve to organise the issues under consideration. First, negotiation protocols are the set of rules that govern the interaction. This covers, the permissible types of participants (e.g., the negotiators and relevant third parties), the negotiation states (e.g., accepting bids, negotiation closed), the events that cause state transitions (e.g., no more bidders, bid accepted), and the valid actions of the participants in particular states (e.g., which can be sent by whom, to whom and at when). Second, negotiation objects are the range of issues over which agreement must be reached. These may single issues, such as price, or multiple issues relating to price, quality, timing, etc. Also relevant here are the allowable operations on these objects. In the simplest case, the structure and contents of the agreement are fixed, and negotiation amounts to accepting or rejecting the offer. The next level, however, offers flexibility to change the values of the issues in the negotiation object, through counter-proposals, changing the structure of the negotiation object (by adding guarantees, for example), and so on. Finally, the agents’ reasoning models provide the decision making apparatus by which participants attempt to achieve their objectives. The sophistication of the model is determined by the protocol used, the nature of the negotiation object, and the range of operations that can be performed on it. The range of problems and issues in this area is clearly wide, yet they can be considered as fundamental to many forms of interaction. To focus discussion, the panelists were asked seven questions that were felt to be key to negotiation. Each of the questions are presented below along with a summary of the responses of the panelists.