TITLE: A LOGICAL APPROACH TO FORMALISING NEGOTIATION IN MULTI-AGENT SYSTEMS Running Head: Negotiation in Multi-Agent Systems Authors and Affiliations:

A new view of multi-agent systems is emerging within a variety of scholarly fields, from distributed artificial intelligence to sociology and organisation science. The hallmark of this view is a recognition of multi-agent systems as inherently complex and computational systems in which cognition occurs at multiple levels, not only within the individual agent, but as an emergent phenomenon from the interaction among multiple agents. According to this perspective, elucidating mechanisms of joint behaviour that are predicated on fully explicated models of agents' cognition at the individual and joint levels remains a key problem for multi-agent system research and practice. In this paper, a step in this direction is taken. We present a theory of negotiation, herein conceptualised as a mechanism for the social and cognitive integration of socially and cognitively differentiated agents. To this end, a new quantified multi-modal logical language is developed that allows us to reason about and represent agents' mental attitudes and their interplay. Drawing on this language, a model of negotiation is then formalised using the classical axiomatic-deductive methodology for theory building. Assumptions of the model are presented, and properties are discussed on a proof-theoretic basis. The descriptive breadth of the theory is illustrated by looking at its computational benefits and applicability when faced with a variety of real-world constraints, such as the agents' bounded rationality, informational asymmetry, and opportunistic behaviour.