Journal of Logic Programming
Journal of Intelligent Information Systems - Special issue on methodologies for intelligent systems
Description logics of minimal knowledge and negation as failure
ACM Transactions on Computational Logic (TOCL)
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
The description logic handbook: theory, implementation, and applications
The description logic handbook: theory, implementation, and applications
Ontology-Based Search for Interactive Digital Maps
IEEE Intelligent Systems
Tractable Reasoning and Efficient Query Answering in Description Logics: The DL-Lite Family
Journal of Automated Reasoning
Reasoning in Description Logics by a Reduction to Disjunctive Datalog
Journal of Automated Reasoning
Query Answering in the Description Logic Horn-$\mathcal{SHIQ}$
JELIA '08 Proceedings of the 11th European conference on Logics in Artificial Intelligence
Bridging the gap between OWL and relational databases
Web Semantics: Science, Services and Agents on the World Wide Web
EQL-lite: effective first-order query processing in description logics
IJCAI'07 Proceedings of the 20th international joint conference on Artifical intelligence
IJCAI'05 Proceedings of the 19th international joint conference on Artificial intelligence
Effective query rewriting with ontologies over DBoxes
IJCAI'09 Proceedings of the 21st international jont conference on Artifical intelligence
Conjunctive query answering in the description logic EL using a relational database system
IJCAI'09 Proceedings of the 21st international jont conference on Artifical intelligence
The DL-lite family and relations
Journal of Artificial Intelligence Research
Reconciling description logics and rules
Journal of the ACM (JACM)
DO-ROAM: activity-oriented search and navigation with OpenStreetMap
GeoS'11 Proceedings of the 4th international conference on GeoSpatial semantics
Epistemic querying of OWL knowledge bases
ESWC'11 Proceedings of the 8th extended semantic web conference on The semantic web: research and applications - Volume Part I
Query Answering with DBoxes is Hard
Electronic Notes in Theoretical Computer Science (ENTCS)
Local closed world semantics: grounded circumscription for OWL
ISWC'11 Proceedings of the 10th international conference on The semantic web - Volume Part I
A general Datalog-based framework for tractable query answering over ontologies
Web Semantics: Science, Services and Agents on the World Wide Web
Hi-index | 0.00 |
When answering queries in the presence of ontologies, adopting the closed world assumption for some predicates easily results in intractability. We analyze this situation on the level of individual ontologies formulated in the description logics DL-Lite and EL and show that in all cases where answering conjunctive queries (CQs) with (open and) closed predicates is tractable, it coincides with answering CQs with all predicates assumed open. In this sense, CQ answering with closed predicates is inherently intractable. Our analysis also yields a dichotomy between AC0 and CONP for CQ answering w.r.t. ontologies formulated in DL-Lite and a dichotomy between PTIME and CONP for EL. Interestingly, the situation is less dramatic in the more expressive description logic ELI, where we find ontologies for which CQ answering is in PTIME, but does not coincide with CQ answering where all predicates are open.