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Document spanners: from expressive power to decision problems
conference contribution
posted on 2017-03-10, 11:22 authored by Dominik FreydenbergerDominik Freydenberger, Mario Holldack© 2016 Dominik D. Freydenberger and Mario Holldack.We examine document spanners, a formal framework for information extraction that was introduced by Fagin et al. (PODS 2013). A document spanner is a function that maps an input string to a relation over spans (intervals of positions of the string). We focus on document spanners that are defined by regex formulas, which are basically regular expressions that map matched subexpressions to corresponding spans, and on core spanners, which extend the former by standard algebraic operators and string equality selection. First, we compare the expressive power of core spanners to three models - namely, patterns, word equations, and a rich and natural subclass of extended regular expressions (regular expressions with a repetition operator). These results are then used to analyze the complexity of query evaluation and various aspects of static analysis of core spanners. Finally, we examine the relative succinctness of different kinds of representations of core spanners and relate this to the simplification of core spanners that are extended with difference operators.
History
School
- Science
Department
- Computer Science
Published in
Leibniz International Proceedings in Informatics, LIPIcsVolume
48Citation
FREYDENBERGER, D.D. and HOLLDACK, M., 2016. Document spanners: from expressive power to decision problems. Presented at the 19th International Conference on Database Theory (ICDT 2016), Bordeaux, France, Mar 15-18th.Publisher
Schloss Dagstuhl – Leibniz Center for InformaticsVersion
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/Publication date
2016Notes
This is an Open Access Article. It is published by Schloss Dagstuhl under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/ISBN
9783959770026ISSN
1868-8969Publisher version
Book series
Leibniz International Proceedings in Informatics, (LIPIcs);48Language
- en