3 Search Results for "Thompson, Sam M."

Document
DOI: 10.4230/LIPIcs.ICDT.2022.10
Splitting Spanner Atoms: A Tool for Acyclic Core Spanners

Authors: Dominik D. Freydenberger and Sam M. Thompson

Published in: LIPIcs, Volume 220, 25th International Conference on Database Theory (ICDT 2022)

Abstract
This paper investigates regex CQs with string equalities (SERCQs), a subclass of core spanners. As shown by Freydenberger, Kimelfeld, and Peterfreund (PODS 2018), these queries are intractable, even if restricted to acyclic queries. This previous result defines acyclicity by treating regex formulas as atoms. In contrast to this, we propose an alternative definition by converting SERCQs into FC-CQs - conjunctive queries in FC, a logic that is based on word equations. We introduce a way to decompose word equations of unbounded arity into a conjunction of binary word equations. If the result of the decomposition is acyclic, then evaluation and enumeration of results become tractable. The main result of this work is an algorithm that decides in polynomial time whether an FC-CQ can be decomposed into an acyclic FC-CQ. We also give an efficient conversion from synchronized SERCQs to FC-CQs with regular constraints. As a consequence, tractability results for acyclic relational CQs directly translate to a large class of SERCQs.
Cite as

Dominik D. Freydenberger and Sam M. Thompson. Splitting Spanner Atoms: A Tool for Acyclic Core Spanners. In 25th International Conference on Database Theory (ICDT 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 220, pp. 10:1-10:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{freydenberger_et_al:LIPIcs.ICDT.2022.10,
  author =	{Freydenberger, Dominik D. and Thompson, Sam M.},
  title =	{{Splitting Spanner Atoms: A Tool for Acyclic Core Spanners}},
  booktitle =	{25th International Conference on Database Theory (ICDT 2022)},
  pages =	{10:1--10:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-223-5},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{220},
  editor =	{Olteanu, Dan and Vortmeier, Nils},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2022.10},
  URN =		{urn:nbn:de:0030-drops-158843},
  doi =		{10.4230/LIPIcs.ICDT.2022.10},
  annote =	{Keywords: Document spanners, information extraction, conjunctive queries}
}
Document
Track B: Automata, Logic, Semantics, and Theory of Programming
DOI: 10.4230/LIPIcs.ICALP.2021.130
The Theory of Concatenation over Finite Models

Authors: Dominik D. Freydenberger and Liat Peterfreund

Published in: LIPIcs, Volume 198, 48th International Colloquium on Automata, Languages, and Programming (ICALP 2021)

Abstract
We propose FC, a new logic on words that combines finite model theory with the theory of concatenation - a first-order logic that is based on word equations. Like the theory of concatenation, FC is built around word equations; in contrast to it, its semantics are defined to only allow finite models, by limiting the universe to a word and all its factors. As a consequence of this, FC has many of the desirable properties of FO on finite models, while being far more expressive than FO[<]. Most noteworthy among these desirable properties are sufficient criteria for efficient model checking, and capturing various complexity classes by adding operators for transitive closures or fixed points. Not only does FC allow us to obtain new insights and techniques for expressive power and efficient evaluation of document spanners, but it also provides a general framework for logic on words that also has potential applications in other areas.
Cite as

Dominik D. Freydenberger and Liat Peterfreund. The Theory of Concatenation over Finite Models. In 48th International Colloquium on Automata, Languages, and Programming (ICALP 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 198, pp. 130:1-130:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{freydenberger_et_al:LIPIcs.ICALP.2021.130,
  author =	{Freydenberger, Dominik D. and Peterfreund, Liat},
  title =	{{The Theory of Concatenation over Finite Models}},
  booktitle =	{48th International Colloquium on Automata, Languages, and Programming (ICALP 2021)},
  pages =	{130:1--130:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-195-5},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{198},
  editor =	{Bansal, Nikhil and Merelli, Emanuela and Worrell, James},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2021.130},
  URN =		{urn:nbn:de:0030-drops-141997},
  doi =		{10.4230/LIPIcs.ICALP.2021.130},
  annote =	{Keywords: finite model theory, word equations, descriptive complexity, model checking, document spanners}
}
Document
DOI: 10.4230/LIPIcs.ICDT.2020.11
Dynamic Complexity of Document Spanners

Authors: Dominik D. Freydenberger and Sam M. Thompson

Published in: LIPIcs, Volume 155, 23rd International Conference on Database Theory (ICDT 2020)

Abstract
The present paper investigates the dynamic complexity of document spanners, a formal framework for information extraction introduced by Fagin, Kimelfeld, Reiss, and Vansummeren (JACM 2015). We first look at the class of regular spanners and prove that any regular spanner can be maintained in the dynamic complexity class DynPROP. This result follows from work done previously on the dynamic complexity of formal languages by Gelade, Marquardt, and Schwentick (TOCL 2012). To investigate core spanners we use SpLog, a concatenation logic that exactly captures core spanners. We show that the dynamic complexity class DynCQ is more expressive than SpLog and therefore can maintain any core spanner. This result is then extended to show that DynFO can maintain any generalized core spanner and that DynFO is more powerful than SpLog with negation.
Cite as

Dominik D. Freydenberger and Sam M. Thompson. Dynamic Complexity of Document Spanners. In 23rd International Conference on Database Theory (ICDT 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 155, pp. 11:1-11:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

Copy BibTex To Clipboard

@InProceedings{freydenberger_et_al:LIPIcs.ICDT.2020.11,
  author =	{Freydenberger, Dominik D. and Thompson, Sam M.},
  title =	{{Dynamic Complexity of Document Spanners}},
  booktitle =	{23rd International Conference on Database Theory (ICDT 2020)},
  pages =	{11:1--11:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-139-9},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{155},
  editor =	{Lutz, Carsten and Jung, Jean Christoph},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2020.11},
  URN =		{urn:nbn:de:0030-drops-119355},
  doi =		{10.4230/LIPIcs.ICDT.2020.11},
  annote =	{Keywords: Document spanners, information extraction, dynamic complexity, descriptive complexity, word equations}
}
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