OWL%201.1%20Rules

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OWL 1.1 Rules

• Markus Krötzsch Sebastian Rudolph
  Pascal Hitzler
• AIFB, University of Karlsruhe, Germany
• logic.aifb.uni-karlsruhe.de
• Deduktionstreffen, Saarbrücken, March 2008

Slide 1
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Neuerscheinung

• Hitzler, Krötzsch, Rudolph, SureSemantic Web
  Grundlagen.Springer, 2008.24,95
• Erstes deutsches Lehrbuch zu Grundlagen des
  Semantic Web.
• Behandelt u.a. Syntax, Semantik und
  Deduktionsverfahren von OWL (SHOIN(D)).

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Web Ontology Language OWL

• Semantic Web Knowledge Representation Language
• W3C recommendation April 2004.
• OWL DL Fragment of 1st order predicate logic.
• OWL DL
• Description Logic SHOIN(D).
• decidable.
• NExpTime

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OWL1.1

• Description Logic SROIQ
• in standardisation process (W3C)
• decidable, NExpTime-hard
• extends SHOIN with
• role inclusion axioms R S v T
• qualified number restrictions
• punning
• further role properties
• identified tractable fragmentsEL, DL-Lite,
  DLP, Horn-SHIQ, ...

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DL Rules

• Rules over some description logic L
• B, H sets of concept or role atoms in L, x the
  variables in B and H
• Rules of the form (8x) B ! H with
• for any non-initial individual u in B, there is a
  path from exactly one initial t to u in B
• for any t,u there is at most one path in B from t
  to u
• if H contains an atom C(t) or R(t,u), then t is
  initial in B

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SROIQ Rules

• can be internalised into SROIQ
• internalisation is polynomial
• however, it is not an obvious transformation
• decidable fragment of SWRL within SROIQ

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EL Rules

• substantially extends EL
• EL together with EL Rules are tractable (in
  P)
• EL can be reduced to EL Rules
• reduction is polynomial
• This allows to apply rule-based reasoning
  techniques for reasoning with EL and EL
  Rules!

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DLP1.1 DLP DLP Rules

• Reducible to function-free first-order Horn rules
  with at most five variables per formula.
• Reduction can be done in polynomial time.
• DLP1.1 is tractable (in P)

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Conclusions

• OWL1.1 Rules as expressive rules fragment of
  OWL1.1.
• Automatically supported by OWL1.1 reasoners.
• EL Rules as new tractable fragment includes
  EL.
• DLP1.1 new tractable rules fragment extending
  DLP.

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• More Details at the Poster!
• THANKS!