Practical undoability checking via contingent planning

Abstract

We consider a general concept of undoability, asking whether a given action can always be undone, no matter which state it is applied to. This generalizes previous concepts of invertibility, and is relevant for search as well as applications. Naïve undoability checking requires to enumerate all states an action is applicable to. Extending and operationalizing prior work in this direction, we introduce a compilation into contingent planning, replacing such enumeration by standard techniques handling large belief states. We furthermore introduce compilations for checking whether one can always get back to an at-least-as-good state, as well as for determining partial undoability, i. e., undoability on a subset of states an action is applicable to. Our experiments on IPC benchmarks and in a cloud management application show that contingent planners are often effective at solving this kind of problem, hence providing a practical means for undoability checking.