OWL 1.1 Rules

Hitzler ● OWL1.1 Rules ● DedSys Saarbrücken ● March 2008

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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


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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

V V


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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!

OWL 1.1 Rules

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