ABSTRACT. In this paper, we investigate the use of event models for automated planning. Event models are the action defining structures used to define a semantics for dynamic epistemic logic. Using event models, two issues in planning can be addressed: Partial observability of the environment and knowledge. In planning, partial observability gives rise to an uncertainty about the world. For single-agent domains, this uncertainty can come from incomplete knowledge of the starting situation and from the nondeterminism of actions. In multi-agent domains, an additional uncertainty arises from the fact that other agents can act in the world, causing changes that are not instigated by the agent itself. For an agent to successfully construct and execute plans in an uncertain environment, the most widely used formalism in the literature on automated planning is “belief states”: sets of different alternatives for the current state of the world. Epistemic logic is a significantly more expressive and theoretically better founded method for representing knowledge and ignorance about the world. Further, epistemic logic allows for planning according to the knowledge (and iterated knowledge) of other agents, allowing the specification of a more complex class of planning domains, than those simply concerned with simple facts about the world. We show how to model multi-agent planning problems using

The paper presents a novel action language for multiagent domains, mA+, which generalizes action languages to multi-agent domains. The language allows representation and reasoning about different types of actions such as ontic (world-altering) actions, sensing actions, and announcements. It also allows the specification of agents ’ dynamic awareness w.r.t. action occurrences. mA+ considers three different kinds of awareness role: fully aware, partially aware, and completely ignorant (oblivious) of the action’s occurrence and its effects. The semantics of mA+ relies on states (pointed Kripke models), used to encode the agent’s knowledge and the real state of the world, and is defined by a transition function. The paper identifies a class of definite action theories whose set of initial states is finite and thus can be implemented. Finally, mA+ is related to other formalisms for reasoning about actions in multi-agent domains.