Automated Contract Negotiation and Execution as a System of Constraints

A classification of constraints is proposed that represents not only the individual and negotiated decisions of multiple agents as constraints, but also the exceptions that can occur at execution time. A design of an exception mechanism is then proposed based on task-environment constraints. This mechanism is composed of an informative and a normative component. The informative component functions to update the beliefs of agents about possible exceptions during the negotiation or execution stages of a joint activity. The normative component, on the other hand, places requirements on the agent to reason about such exceptions. The interaction of such an informative mechanism on a bargaining mechanism is elaborated in this paper. A simple additive model of future events is assumed to reasonably model this information. Different agent bargaining strategies, characterized as different attitudes towards the original constraints of the local problem given this belief, are then evaluated for a concession solver in an alternating sequential protocol.