Publication
Title
Structural characterizations of the navigational expressiveness of relation algebras on a tree
Author
Abstract
We study the expressiveness on a given document of various fragments of XPath, the core navigational language on XML documents. Viewing these languages as fragments of Tarski's relation algebra, we give characterizations for when a binary relation on the document's nodes (i.e., a set of paths) is definable by an expression in these algebras. In contrast with this "global view" on language semantics, there is also a "local view" where one is interested in the nodes to which one can navigate starting from a particular node. In this view, we characterize when a set of nodes can be defined as the result of applying an expression to a given node. All of these global and local definability results are obtained using a two-step methodology, which consists of first characterizing when two nodes cannot be distinguished by an expression in the language, and then bootstrapping these characterizations to the desired results. (C) 2015 Elsevier Inc. All rights reserved.
Language
English
Source (journal)
Journal of computer and system sciences. - New York, N.Y.
Publication
New York, N.Y. : 2016
ISSN
0022-0000
Volume/pages
82:2(2016), p. 229-259
ISI
000366240700005
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 15.01.2016
Last edited 03.09.2017
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