منابع مشابه
Axiomatizations for downward XPath on Data Trees
We give sound and complete axiomatizations for XPath with data tests by ‘equality’ or ‘inequality’, and containing the single ‘child’ axis. This data-aware logic predicts over data trees, which are tree-like structures whose every node contains a label from a finite alphabet and a data value from an infinite domain. The language allows us to compare data values of two nodes but cannot access th...
متن کاملDefinability for Downward and Vertical XPath on Data Trees
We study the expressive power of the downward and vertical fragments of XPath equipped with (in)equality tests over data trees. We give necessary and sufficient conditions for a class of pointed data trees to be definable by a set of formulas or by a single formula of each of the studied logics. To do so, we introduce a notion of saturation, and show that over saturated data trees bisimulation ...
متن کاملRewriting XPath queries using materialized XPath views
Let XP(/, //, [ ]) be the fragment of XPath 1.0, consisting of queries that involve only the child and descendant axes, and predicates without disjunction or negation (and no wildcard nodetests); these queries can be represented as tree patterns. We consider the problem of rewriting a query Q using a materialized view V , where Q,V ∈ XP(/, //, [ ]). We present more efficient algorithms for the ...
متن کاملSatisfiability of XPath Expressions
In this paper, we investigate the complexity of deciding the satisfiability of XPath 2.0 expressions, i.e., whether there is an XML document for which their result is nonempty. Several fragments that allow certain types of expressions are classified as either in PTIME or NP-hard to see which type of expression make this a hard problem. Finally, we establish a link between XPath expressions and ...
متن کامل$varepsilon$-Simultaneous approximations of downward sets
In this paper, we prove some results on characterization of $varepsilon$-simultaneous approximations of downward sets in vector lattice Banach spaces. Also, we give some results about simultaneous approximations of normal sets.
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ژورنال
عنوان ژورنال: ACM Transactions on Computational Logic
سال: 2012
ISSN: 1529-3785,1557-945X
DOI: 10.1145/2362355.2362362