126 search results - page 3 / 26 » The Complexity of Acyclic Conjunctive Queries |
DLOG
2006
13 years 9 months ago
2006
The novel context of accessing and querying large data repositories through ontologies that are formalized in terms of expressive DLs requires on the one hand to consider query an...
DLOG
2011
12 years 11 months ago
2011
In order to meet usability requirements, most logic-based applications provide explanation facilities for reasoning services. This holds also for DLs, where research focused on the...
AAAI
2006
13 years 9 months ago
2006
Description Logics (DLs) are the formal foundations of the standard web ontology languages OWL-DL and OWL-Lite. In the Semantic Web and other domains, ontologies are increasingly ...
ERSHOV
2009
Springer
14 years 2 months ago
2009
Springer
Abstract. We consider the problem of query containment for conjunctive queries with safe negation property. A necessary and sufficient condition for two queries to be in containmen...
ICDT
2009
ACM
14 years 8 months ago
2009
ACM
The class of unions of conjunctive queries (UCQ) has been shown to be particularly well-behaved for data exchange; its certain answers can be computed in polynomial time (in terms...