REPRESENTING ACTION - INDETERMINACY AND RAMIFICATIONS

We define and study a high-level language for describing actions, more expressive than the action language A introduced by Gelfond and Lifsc hitz. The new language, AR, allows us to describe actions with indirec t effects (ramifications), nondeterministic actions, and actions that may be impossible to execute. It has symbols for nonpropositional flue nts and for the fluents that are exempt from the commonsense law of in ertia. Temporal projection problems specified using the language AR ca n be represented as nested abnormality theories based on the situation calculus. (C) 1997 Elsevier Science B.V.