The Petri Net is a natural representation for parallel action and synchronization in a multi-agent world [Sowa,2000]. Transitions can represent actions, with input places
corresponding to pre-conditions and output places corresponding to effects. We extend the standard (colored)Petri Net formalism with special kinds of places called
control nodes and belief nodes. Control nodes represent the belief an agent has about the current goals and activities of others in the team. Belief nodes represent the belief an agent has about the world, when coupled with a unification-based theorem-prover, can represent first-order knowledge, including dynamic facts and inferences about the world. In addition to serving as the shared mental model, Petri Nets also play the dual role of monitoring and tracking the execution of team plans.