Semantic characterizations of navigational XPath
نویسندگان
چکیده
منابع مشابه
Semantic Characterizations of Navigational XPath
We give semantic characterizations of the expressive power of navigational XPath (a.k.a. Core XPath) in terms of first order logic. XPath can be used to specify sets of nodes and sets of paths in an XML document tree. We consider both uses. For sets of nodes, XPath is equally expressive as first order logic in two variables. For paths, XPath can be defined using four simple connectives, which t...
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Given a document D in the form of an unordered node-labeled tree, we study the expressiveness on D of various basic fragments of XPath, the core navigational language on XML documents. Working from the perspective of these languages as fragments of Tarski’s relation algebra, we give characterizations, in terms of the structure of D, for when a binary relation on its nodes is definable by an exp...
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ژورنال
عنوان ژورنال: ACM SIGMOD Record
سال: 2005
ISSN: 0163-5808
DOI: 10.1145/1083784.1083792