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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/18681

Title: Relative expressive power of navigational querying on graphs
Authors: Fletcher, George H. L.
GYSSENS, Marc
LEINDERS, Dirk
SURINX, Dimitri
VAN DEN BUSSCHE, Jan
Van Gucht, Dirk
VANSUMMEREN, Stijn
Wu, Yuqing
Issue Date: 2015
Publisher: ELSEVIER SCIENCE INC
Citation: INFORMATION SCIENCES, 298, p. 390-406
Abstract: Motivated by both established and new applications, we study navigational query languages for graphs (binary relations). The simplest language has only the two operators union and composition, together with the identity relation. We make more powerful languages by adding any of the following operators: intersection; set difference; projection; coprojection; converse; and the diversity relation. All these operators map binary relations to binary relations. We compare the expressive power of all resulting languages. We do this not only for general path queries (queries where the result may be any binary relation) but also for boolean or yes/no queries (expressed by the nonemptiness of an expression). For both cases, we present the complete Hasse diagram of relative expressiveness. In particular the Hasse diagram for boolean queries contains some nontrivial separations and a few surprising collapses. (C) 2014 Elsevier Inc. All rights reserved.
Notes: [Fletcher, George H. L.] Eindhoven Univ Technol, NL-5600 MB Eindhoven, Netherlands. [Gyssens, Marc; Leinders, Dirk; Surinx, Dimitri; Van den Bussche, Jan] Hasselt Univ, Diepenbeek, Belgium. [Gyssens, Marc; Leinders, Dirk; Surinx, Dimitri; Van den Bussche, Jan] Transnatl Univ Limburg, Diepenbeek, Belgium. [Van Gucht, Dirk; Wu, Yuqing] Indiana Univ, Bloomington, IN 47405 USA. [Vansummeren, Stijn] Univ Libre Bruxelles, Brussels, Belgium.
URI: http://hdl.handle.net/1942/18681
DOI: 10.1016/j.ins.2014.11.031
ISI #: 000349590000022
ISSN: 0020-0255
Category: A1
Type: Journal Contribution
Validation: ecoom, 2016
Appears in Collections: Research publications

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