Reasoning about concurrent execution, prioritized interrupts, and exogenous actions in the situation calculus

Abstract

As an alternative to planning, an approach to high-level agent control based on concurrent program execution is considered. A formal definition in the situation calculus of such a programming language is presented and illustrated with a detailed example. The language includes facilities for prioritizing the concurrent execution, interrupting the execution when certain conditions become true, and dealing with exogenous actions. The language differs from other procedural formalisms for concurrency in that the initial state can be incompletely specified and the primitive actions can be userdefined by axioms in the situation calculus. When it comes to providing high-level control for robots or other agents in dynamic and incompletely known worlds, approaches based on plan synthesis may end up being too demanding computationally in all but simple settings. An alternative approach that is showing promise is that of high-level program execution [8]. The idea, roughly, is that instead of searc...