Monotonic concession protocols for multilateral negotiation

The most natural way of thinking about negotiation is probably a situation whereby each of the parties involved initially make a proposal that is particularly beneficial to themselves and then incrementally revise their earlier proposals in order to come to an agreement. This idea has been formalised in the so-called monotonic concession protocol, a set of rules defining the range of acceptable moves during a negotiation process intended to follow this general scheme. In the case of negotiation between just two agents, the monotonic concession protocol has become a textbook example and its formal properties are well-understood. In the case of multilateral negotiation, where more than two agents need to come to an agreement, on the other hand, it is not at all clear how to set up a monotonic concession protocol. As it turns out, the design of such a protocol boils down to the question of what constitutes a multilateral concession. In this paper, we make several proposals as to what might be an appropriate definition and analyse the properties of the proposed concession criteria.