|
Abstract : |
A previous paper introduced the nonmonotonic formalism of causal theories, along with a general method for representing action domains in it. Here we show that causal action theories provide a basis for effective automated planning. To this end, we define several properties plans may have, such as executability, determinism, and validity. We then identify a class of causal action theories for which (i) there is a concise translation into classical logic, and (ii) the models of the resulting classical theories correspond to valid plans. These results enable satisfiability planning (in the sense of Kautz and Selman) on the basis of action formalizations that include indirect effects of actions (ramifications), implied action preconditions (qualifications), concurrent actions, and other features of action domains. Causal theories representing the large blocks world and logistics planning problems from [Kautz and Selman, 1996] are solved comparatively quickly, demonstrating the effectiveness of our approach., |
