License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ICALP.2019.104
URN: urn:nbn:de:0030-drops-106803
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2019/10680/
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Barceló, Pablo ; Figueira, Diego ; Romero, Miguel

Boundedness of Conjunctive Regular Path Queries

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Abstract

We study the boundedness problem for unions of conjunctive regular path queries with inverses (UC2RPQs). This is the problem of, given a UC2RPQ, checking whether it is equivalent to a union of conjunctive queries (UCQ). We show the problem to be ExpSpace-complete, thus coinciding with the complexity of containment for UC2RPQs. As a corollary, when a UC2RPQ is bounded, it is equivalent to a UCQ of at most triple-exponential size, and in fact we show that this bound is optimal. We also study better behaved classes of UC2RPQs, namely acyclic UC2RPQs of bounded thickness, and strongly connected UCRPQs, whose boundedness problem is, respectively, PSpace-complete and Pi_2^P-complete. Most upper bounds exploit results on limitedness for distance automata, in particular extending the model with alternation and two-wayness, which may be of independent interest.

BibTeX - Entry

@InProceedings{barcel_et_al:LIPIcs:2019:10680,
  author =	{Pablo Barcel{\'o} and Diego Figueira and Miguel Romero},
  title =	{{Boundedness of Conjunctive Regular Path Queries}},
  booktitle =	{46th International Colloquium on Automata, Languages, and Programming (ICALP 2019)},
  pages =	{104:1--104:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-109-2},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{132},
  editor =	{Christel Baier and Ioannis Chatzigiannakis and Paola Flocchini and Stefano Leonardi},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2019/10680},
  URN =		{urn:nbn:de:0030-drops-106803},
  doi =		{10.4230/LIPIcs.ICALP.2019.104},
  annote =	{Keywords: regular path queries, boundedness, limitedness, distance automata}
}

Keywords: regular path queries, boundedness, limitedness, distance automata
Collection: 46th International Colloquium on Automata, Languages, and Programming (ICALP 2019)
Issue Date: 2019
Date of publication: 04.07.2019

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