A nonmonotonic theory of planning
Salvinder Singh Hundal · 1992
A nonmonotonic theory of planning that uses nonmonotonic reasoning based on the modal quantificational logic Z is devised. The proposed theory uses a modal frame axiom and the modal quantificational logic Z to propagate the facts from the current situation to the next situation. Only the most obvious consequences of each action need to be described by the user, since the unobvious consequences are inferred from the frame axioms, no delete list is needed. Facts are automatically added and deleted from one situation to the next by nonmonotonic reasoning as the actions are executed. Also, a nonmonotonic theory of plan synthesis is developed, which reasons about actions and the plan synthesis to detect possible or impossible orderings of the actions that reduces the search space. A plan synthesis algorithm is given, which builds a plan incrementally by inserting new actions into the plan or by modifying the plan using the nonmonotonic reasoning system of the modal quantificational logic Z. The algorithm has been implemented as a computer program, called the frame planner, in the Schemata Deduction Language and the nonmonotonic modal quantificational logic Z system, which is currently running on a Symbolics$\sp{\rm TM}$ Lisp Machine.