Prima facie obligations and a deontic transaction model for multiagent systems

To secure the consistency and integrity of extended multiagent actions, we subsume them under the transaction abstraction. Deontic logic, the logic of normative reasoning is used to develop a transaction model for multiagent systems. Obligations are seen as arising from speech acts of the agents in the transaction, and they structure the transaction into a hierarchy of subtransactions. A prima facie obligation is one that binds unless overridden by another obligation. We emphasize such defeasibility of obligations and exploit Y.U. Ryu's (1995; 1997) defeasible deontic logic. Our model accounts for the flexibility and fault tolerance of multiagent systems, the autonomy of agents, and the importance of negotiation.