25 search results - page 2 / 5 » Equivalence and minimization of conjunctive queries under co... |
ICDT
2009
ACM
14 years 6 months ago
2009
ACM
We study containment and equivalence of (unions of) conjunctive queries on relations annotated with elements of a commutative semiring. Such relations and the semantics of positiv...
DLOG
2007
13 years 8 months ago
2007
We present cq-programs, which enhance nonmonotonic description logics (dl-) programs by conjunctive queries (CQ) and union of conjunctive queries (UCQ) over Description Logics kno...
BNCOD
2009
13 years 6 months ago
2009
We study the expressiveness of a positive fragment of path queries, denoted Path+ , on node-labeled trees documents. The expressiveness of Path+ is studied from two angles. First, ...
WWW
2011
ACM
13 years 21 days ago
2011
ACM
The problem of answering SPARQL queries over virtual SPARQL views is commonly encountered in a number of settings, including while enforcing security policies to access RDF data, ...
RR
2009
Springer
14 years 9 days ago
2009
Springer
Abstract. It is well-knwon that crisp RDF is not suitable to represent vague information. Fuzzy RDF variants are emerging to overcome to this limitations. In this work we provide, ...