PSIPLAN: open world planning with Ψ-forms
Tamara Babaian, James G. Schmolze · 2000
We present a new partial order planner called PSI-PLAN, which builds on SNLP. We drop the closed world assumption, add sensing actions, add a class of propositions about the agent’s knowledge, and add a class of universally quantified propositions. This lat-ter class of propositions, which we call ψ-forms, dis-tinguishes this research. ψ-forms represent partially closed worlds, such as “Block A is clear”, or “x.ps is the only postscript file in directory /tex. ” We present our theory of planning with sensing and show how par-tial order planning is performed using ψ-forms. Note-worthy are the facts that lack of information can be represented precisely and all quantified reasoning has polynomial complexity. Thus, in finite domains where the maximum plan length is bounded, planning with PSIPLAN is NP-complete.