Knowledge Preconditions for Plans

For an agent to be able to rely on a plan, he must know both that he is physically capable of carrying out the physical actions involved, and that he knows enough to carry out the plan. In this talk, we advance and discuss new de nitions of \knowing enough to carry out a plan", for the case of a single agent carrying out a sequence of primitive actions one at a time. We consider both determinate and indeterminate plans. We show how these de nition can be expressed in a formal logic, using a situation calculus model of time and a possible worlds model of knowledge. The de nitions strictly subsume previous theories for the single-agent case without concurrent actions. We illustrate the power of the de nition by showing that it supports results of the following kinds: Positive veri cation: Showing that a plan is feasible. Negative veri cation: Showing that a plan is infeasible. Monotonicity: The more an agent knows, the more plans are executable. Reduction for omniscient agent: For an omniscient agent, a plan is epistemically feasible if and only if it is physically feasible. Simple recursive rules that are suÆcient conditions for the feasibility of a plan described as a sequence or a conditional combination of subplans.