Our seminar series is free and available for anyone to attend. Unless otherwise stated, seminars take place on Wednesday afternoons at 2pm in the Kilburn Building during teaching season.

If you wish to propose a seminar speaker please contact Antoniu Pop.


Why Small Description Logics Deserve more Love.

  • Speaker:   Dr  Sebastian Brandt  (TU Dresden)
  • Host:   Uli Sattler
  • 16th November 2005 at 14:15 in 1.5
The quest for tractable description logics (DLs) was until recently restricted to DLs extending the basic language FL_0, which allows for conjunction and value restrictions. However, as soon as terminologies (TBoxes) are taken into consideration, tractability turns out to be unattainable---especially in the presence of general concept inclusion axioms (GCIs) supported by most modern DL systems, such as FaCT or Racer. Because of a need for both expressive DLs and GCIs in applications, the DL community has mainly given up on the quest for tractable DLs.

Recently, the choice of value restrictions as a sine qua non of DLs has been reconsidered. On the one hand, it was shown that the DL EL, which allows for conjunction and existential restrictions, has better algorithmic properties than FL_0. On the other hand, there are applications where the expressive power of EL or small extensions thereof appear sufficient. Moreover, knowledge engineering tasks, such as build-up and maintenance of EL-TBoxes, can be facilitated even in the presence of GCIs by means of so-called non-standard inference services.

The aim of my talk is to give an overview of both foundations and current state of the art of tractable reasoning in EL and some of its extensions. In this context, reasoning w.r.t.\ GCIs and non-standard inference problems will be of particular interest.
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