1. x) in Figure 5, refers to a private belief
held by each agent in the team that they each believe that a fact x is true, and that each of the
other agents in the team believe that x is true, and that every agent believes that every other
agent believes that x is true and so on. Such infinite levels of nesting are difficult to realize in
practice. Thus, as in practical BDI implementations, for the purposes of this article, a mutual belief is
approximated to be a private belief held by an agent that all the agents in the team believe that x is
true.