Computing Datalog Rewritings Beyond Horn Ontologies

Rewriting-based approaches for answering queries over an OWL 2 DL ontology have so far been developed mainly for Horn fragments of OWL 2 DL. In this paper, we study the possibilities of answering queries over non-Horn ontologies using datalog rewritings. We prove that this is impossible in general even for very simple ontology languages, and even if PTIME = NP. Furthermore, we present a resolution-based procedure for SHI ontologies that, in case it terminates, produces a datalog rewriting of the ontology. We also show that our procedure necessarily terminates on DL-LiteboolH,+ ontologies--an extension of OWL 2 QL with transitive roles and Boolean connectives.

[1]  Zhe Wu,et al.  Implementing an Inference Engine for RDFS/OWL Constructs and User-Defined Rules in Oracle , 2008, 2008 IEEE 24th International Conference on Data Engineering.

[2]  Ian Horrocks,et al.  Description logic programs: combining logic programs with description logic , 2003, WWW '03.

[3]  Carsten Lutz,et al.  Non-Uniform Data Complexity of Query Answering in Description Logics , 2012, Description Logics.

[4]  Ingo Wegener,et al.  The complexity of Boolean functions , 1987 .

[5]  Sebastian Rudolph,et al.  Query Answering in the Horn Fragments of the Description Logics SHOIQ and SROIQ , 2011, IJCAI.

[6]  Boris Motik,et al.  Reasoning in Description Logics by a Reduction to Disjunctive Datalog , 2007, Journal of Automated Reasoning.

[7]  Ian Horrocks,et al.  Conjunctive Query Answering for the Description Logic SHIQ , 2007, IJCAI.

[8]  Boris Motik,et al.  Completeness Guarantees for Incomplete Ontology Reasoners: Theory and Practice , 2014, J. Artif. Intell. Res..

[9]  Riccardo Rosati,et al.  Improving Query Answering over DL-Lite Ontologies , 2010, KR.

[10]  Carsten Lutz,et al.  Data Complexity in the EL Family of Description Logics , 2007, LPAR.

[11]  Frantisek Simancik,et al.  Elimination of Complex RIAs without Automata , 2012, Description Logics.

[12]  Boris Motik,et al.  Hypertableau Reasoning for Description Logics , 2009, J. Artif. Intell. Res..

[13]  Boris Motik,et al.  Data Complexity of Reasoning in Very Expressive Description Logics , 2005, IJCAI.

[14]  Giorgos B. Stamou,et al.  Optimized Query Rewriting for OWL 2 QL , 2011, CADE.

[15]  Barry Bishop,et al.  OWLIM: A family of scalable semantic repositories , 2011, Semantic Web.

[16]  Boris Motik,et al.  Tractable query answering and rewriting under description logic constraints , 2010, J. Appl. Log..

[17]  Alvaro del Val.  First order LUB approximations: characterization and algorithms , 2005, Artif. Intell..

[18]  Bart Selman,et al.  Knowledge compilation and theory approximation , 1996, JACM.

[19]  Franz Baader,et al.  Pushing the EL Envelope , 2005, IJCAI.

[20]  Mihalis Yannakakis,et al.  On Datalog vs. Polynomial Time , 1995, J. Comput. Syst. Sci..

[21]  Thomas Eiter,et al.  Query Rewriting for Horn-SHIQ Plus Rules , 2012, AAAI.

[22]  Diego Calvanese,et al.  High Performance Query Answering over DL-Lite Ontologies , 2012, KR.

[23]  Diego Calvanese,et al.  Tractable Reasoning and Efficient Query Answering in Description Logics: The DL-Lite Family , 2007, Journal of Automated Reasoning.

[24]  CalvaneseDiego,et al.  The DL-lite family and relations , 2009 .

[25]  Diego Calvanese,et al.  The DL-Lite Family and Relations , 2009, J. Artif. Intell. Res..

[26]  Journal of automated reasoning , 1986 .

[27]  Diego Calvanese,et al.  The description logic handbook: theory , 2003 .

[28]  Carsten Lutz,et al.  The Complexity of Conjunctive Query Answering in Expressive Description Logics , 2008, IJCAR.

[29]  Diego Calvanese,et al.  QuOnto: Querying Ontologies , 2005, AAAI.

[30]  Markus Stocker,et al.  Owlgres: A Scalable OWL Reasoner , 2008, OWLED.

[31]  Diego Calvanese,et al.  The Description Logic Handbook: Theory, Implementation, and Applications , 2003, Description Logic Handbook.