We now know that the addition of a concept constructor called a Path Functional Dependency (PFD) to the Boolean-complete description logic DLF leads to undecidability of ABox consistency for DLF. Consequently, we define a boundary condition for PFDs that enables the recovery of earlier DLF complexity bounds for this problem. This is accomplished indirectly by adding an additional concept constructor for rooted path equality, which has the added benefit of increasing the utility of DLF for reasoning about query containment problems in query optimization, in plan generation and in automated sythesis of web services.
Vitaliy L. Khizder, David Toman, Grant E. Weddell