Backtracking and Qualified Number Restrictions: Some Preliminary Results.
Ian Horrocks · 2002
Description Logics (DLs) are useful in the database domain, where they can be used to reason, e.g., about conceptual schemas and query containment. DL knowledge bases derived from relatively small UML diagrams have, however, proven difficult of impossible for state of the art DL systems to solve. We show that in the FaCT system this problem results from the failure of dependency directed backtracking to prune the search space caused by non-deterministic expansion of qualified number restrictions. We present an enhanced dependency directed backtracking technique that is able to deal more effectively with these constructs, along with empirical results demonstrating that, after the addition of this enhanced technique, the FaCT system is able to deal much more effectively with UML derived KBs. 1