Structural Properties of XPath Fragments

Benedikt, Michael and Fan, Wenfei and Kuper, Gabriel M. (2002) Structural Properties of XPath Fragments. UNSPECIFIED. (Unpublished)

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    We study structural properties of each of the main sublanguages of XPath~\cite{xpath} commonly used in practice. First, we characterize the expressive power of these language fragments in terms of both logics and tree patterns. Second, we investigate closure properties, focusing on the ability to perform basic Boolean operations while remaining within the fragment. We give a complete picture of the closure properties of these fragments, treating XPath expressions both as functions of arbitrary nodes in a document tree, and as functions that are applied only at the root of the tree. Finally, we provide sound and complete axiom systems and normal forms for several of these fragments. These results are useful for simplification of XPath expressions and optimization of XML queries

    Item Type: Departmental Technical Report
    Department or Research center: Information Engineering and Computer Science
    Subjects: Q Science > QA Mathematics > QA076 Computer software
    Additional Information: Full version of paper. Extended abstract to appear ICDT 2003 (Jan 2003, Siena)
    Report Number: DIT-02-089
    Repository staff approval on: 16 Dec 2002

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