A Logical Theory of Coordination and Joint Ability

A team of agents is jointly able to achieve a goal if despite any incomplete knowledge they may have about the world or each other, they still know enough to be able to get to a goal state. Unlike in the single-agent case, the mere existence of a working plan is not enough as there may be several incompatible working plans and the agents may not be able to choose a share that coordinates with the others’. Some formalizations of joint ability ignore this issue of coordination within a coalition. Others, including those based on game theory, deal with coordination, but require a complete specification of agents’ beliefs. Such a complete specification is often not available. Here we present a new formalization of joint ability based on logical entailment in the situation calculus that avoids both of these pitfalls.