Using Static Graphs in Planning Domains to Understand Domain Dynamics⇤

This paper describes a method for analyzing STRIPS-like planning domains by identifying static graphs that are implicit in the set of operators defining a planning domain. A graph consisting of nodes and possibly directed edges is a common way to construct representations for many problems, including computational problems and problems of reasoning about action. Furthermore, there may be objects or properties related to the nodes of such a graph that may be modified by the operators in ways restricted by the graph. The formal definition of shift operators over static graphs as a domain feature is the main contribution of this paper. Such an analysis could be used for verification and validation of the planning domain when it is presented to the domain author who may or may not agree with the result of the analysis. The method described relies on domain features that can also be extracted automatically, and it works on domains rather than problems, which means the result is problem-independent. However, if problems are given further analysis may be perfomed. The method has been evaluated using a small number of planning domains drawn from the international planning competition.