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Title: Expressiveness and static analysis of extended conjunctive regular path queries
Authors: Freydenberger, Dominik D.
Schweikardt, Nicole
Issue Date: 2013
Publisher: © 2013 Elsevier Inc.
Citation: FREYDENBERGER, D.D. and SCHWEIKARDT, N., 2013. Expressiveness and static analysis of extended conjunctive regular path queries. Journal of Computer and System Sciences, 79 (6), pp.892-909
Abstract: We study the expressiveness and the complexity of static analysis of extended conjunctive regular path queries (ECRPQs), introduced by Barceló et al. (2010) [3]. ECRPQs are an extension of conjunctive regular path querie s (CRPQs), a well-studied language for querying graph structured databases. Our first main result shows that query containment and equivalence of a CRPQ in an ECRPQ are undecidable. This settles one of the main open problems posed by Barceló et al. As a second main result, we prove a non-recursive succinctness gap between CRPQs and the CRPQ-expressible fragment of ECRPQs. Apart from this, we develop a tool for proving inexpressibility results for CRPQs and ECRPQs. In particular, this enables us to show that there exist queries definable by regular expressions with backreferencing, but not expressible by ECRPQs. © 2013 Elsevier Inc.
Description: This paper is a full version of the authors' conference contribution from the 5th Alberto Mendelzon International Workshop on Foundations of Data Management (AMW2011), Santiago, Chile, May 9-12, 2011.
Version: Accepted for publication
DOI: 10.1016/j.jcss.2013.01.008
URI: https://dspace.lboro.ac.uk/2134/26542
Publisher Link: https://doi.org/10.1016/j.jcss.2013.01.008
ISSN: 0022-0000
Appears in Collections:Published Articles (Computer Science)

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