PODS
2007
ACM
14 years 7 months ago
2007
ACM
In a recent paper, Martens et al. introduced a specification mechanism for XML tree languages, based on rules of the form r s, where r, s are regular expressions. Sets of such ru...
PODS
2007
ACM
14 years 7 months ago
2007
ACM
PODS
2007
ACM
14 years 7 months ago
2007
ACM
We show that relational algebra calculations for incomplete databases, probabilistic databases, bag semantics and whyprovenance are particular cases of the same general algorithms...
PODS
2007
ACM
14 years 7 months ago
2007
ACM
Bounded treewidth and Monadic Second Order (MSO) logic have proved to be key concepts in establishing fixed-parameter tractability results. Indeed, by Courcelle's Theorem we ...
PODS
2007
ACM
14 years 7 months ago
2007
ACM
The generalized hypertree width GHW(H) of a hypergraph H is a measure of its cyclicity. Classes of conjunctive queries or constraint satisfaction problems whose associated hypergr...
PODS
2007
ACM
14 years 7 months ago
2007
ACM
PODS
2007
ACM
14 years 7 months ago
2007
ACM
Variables are the distinguishing new feature of XPath 2.0 which permits to select n-tuples of nodes in trees. It is known that the Core of XPath 2.0 captures n-ary first-order (FO...
PODS
2007
ACM
14 years 7 months ago
2007
ACM
PODS
2007
ACM
14 years 7 months ago
2007
ACM
Schema mappings are high-level specifications that describe the relationship between two database schemas. Two operators on schema mappings, namely the composition operator and th...
PODS
2007
ACM
14 years 7 months ago
2007
ACM
The pebble tree automaton and the pebble tree transducer are enhanced by additionally allowing an unbounded number of `invisible' pebbles (as opposed to the usual `visible�...