How to Progress a Database II: The STRIPS Connection

Abstract

Ever since STRIPS was first introduced (Fikes and Nilsson [2]), its logical semantics has been problematic. There have been many proposals in the literature (e.g. Lifschitz [3], Pednault [7], Bacchus and Yang [1]). These all have in common a reliance on meta-theoretic operations on logical theories in order to capture the add and delete lists of STRIPS operators, but it has never been clear exactly what these operations correspond to declaratively, especially when they are applied to logically incomplete theories. In this paper we provide a semantics for STRIPS-like systems in terms of a purely declarative situation calculus axiomatization for actions and their effects. On our view, STRIPS is a mechanism for computing the progression (Lin and Reiter [5]) of an initial situation calculus database under the effects of an action. We illustrate this idea by specifying two different versions of STRIPS in the situation calculus. 1 Fellow of the Canadian Institute for Advanced Research 1 P...