4 Search Results for "Ostropolski-Nalewaja, Piotr"


Document
Finite-Cliquewidth Sets of Existential Rules: Toward a General Criterion for Decidable yet Highly Expressive Querying

Authors: Thomas Feller, Tim S. Lyon, Piotr Ostropolski-Nalewaja, and Sebastian Rudolph

Published in: LIPIcs, Volume 255, 26th International Conference on Database Theory (ICDT 2023)


Abstract
In our pursuit of generic criteria for decidable ontology-based querying, we introduce finite-cliquewidth sets (fcs) of existential rules, a model-theoretically defined class of rule sets, inspired by the cliquewidth measure from graph theory. By a generic argument, we show that fcs ensures decidability of entailment for a sizable class of queries (dubbed DaMSOQs) subsuming conjunctive queries (CQs). The fcs class properly generalizes the class of finite-expansion sets (fes), and for signatures of arity ≤ 2, the class of bounded-treewidth sets (bts). For higher arities, bts is only indirectly subsumed by fcs by means of reification. Despite the generality of fcs, we provide a rule set with decidable CQ entailment (by virtue of first-order-rewritability) that falls outside fcs, thus demonstrating the incomparability of fcs and the class of finite-unification sets (fus). In spite of this, we show that if we restrict ourselves to single-headed rule sets over signatures of arity ≤ 2, then fcs subsumes fus.

Cite as

Thomas Feller, Tim S. Lyon, Piotr Ostropolski-Nalewaja, and Sebastian Rudolph. Finite-Cliquewidth Sets of Existential Rules: Toward a General Criterion for Decidable yet Highly Expressive Querying. In 26th International Conference on Database Theory (ICDT 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 255, pp. 18:1-18:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


Copy BibTex To Clipboard

@InProceedings{feller_et_al:LIPIcs.ICDT.2023.18,
  author =	{Feller, Thomas and Lyon, Tim S. and Ostropolski-Nalewaja, Piotr and Rudolph, Sebastian},
  title =	{{Finite-Cliquewidth Sets of Existential Rules: Toward a General Criterion for Decidable yet Highly Expressive Querying}},
  booktitle =	{26th International Conference on Database Theory (ICDT 2023)},
  pages =	{18:1--18:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-270-9},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{255},
  editor =	{Geerts, Floris and Vandevoort, Brecht},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2023.18},
  URN =		{urn:nbn:de:0030-drops-177602},
  doi =		{10.4230/LIPIcs.ICDT.2023.18},
  annote =	{Keywords: existential rules, TGDs, cliquewidth, treewidth, bounded-treewidth sets, finite-unification sets, first-order rewritability, monadic second-order logic, datalog}
}
Document
Invited Talk
What Makes a Variant of Query Determinacy (Un)Decidable? (Invited Talk)

Authors: Jerzy Marcinkowski

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


Abstract
This paper was written as the companion paper of the ICDT 2020 invited tutorial. Query determinacy is a broad topic, with literally hundreds of papers published since late 1980s. This paper is not going to be a "survey" but rather a personal perspective of a person somehow involved in the recent developments in the area. First I explain how, in the last 30+ years, the question of determinacy was formalized. There are many parameters here: obviously one needs to choose the query language of the available views and the query language of the query itself. But - surprisingly - there is also some choice regarding what the word "to compute" actually means in this context. Then I concentrate on certain variants of the decision problem of determinacy (for each choice of parameters there is one such problem) and explain how I understand the mechanisms rendering such variants of determinacy decidable or undecidable. This is on a rather informal level. No really new theorems are presented, but I show some improvements of existing theorems and also simplified proofs of some of the earlier results.

Cite as

Jerzy Marcinkowski. What Makes a Variant of Query Determinacy (Un)Decidable? (Invited Talk). In 23rd International Conference on Database Theory (ICDT 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 155, pp. 2:1-2:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


Copy BibTex To Clipboard

@InProceedings{marcinkowski:LIPIcs.ICDT.2020.2,
  author =	{Marcinkowski, Jerzy},
  title =	{{What Makes a Variant of Query Determinacy (Un)Decidable?}},
  booktitle =	{23rd International Conference on Database Theory (ICDT 2020)},
  pages =	{2:1--2:20},
  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.2020.2},
  URN =		{urn:nbn:de:0030-drops-119265},
  doi =		{10.4230/LIPIcs.ICDT.2020.2},
  annote =	{Keywords: database theory, query, view, determinacy}
}
Document
The First Order Truth Behind Undecidability of Regular Path Queries Determinacy

Authors: Grzegorz Głuch, Jerzy Marcinkowski, and Piotr Ostropolski-Nalewaja

Published in: LIPIcs, Volume 127, 22nd International Conference on Database Theory (ICDT 2019)


Abstract
In our paper [Głuch, Marcinkowski, Ostropolski-Nalewaja, LICS ACM, 2018] we have solved an old problem stated in [Calvanese, De Giacomo, Lenzerini, Vardi, SPDS ACM, 2000] showing that query determinacy is undecidable for Regular Path Queries. Here a strong generalisation of this result is shown, and - we think - a very unexpected one. We prove that no regularity is needed: determinacy remains undecidable even for finite unions of conjunctive path queries.

Cite as

Grzegorz Głuch, Jerzy Marcinkowski, and Piotr Ostropolski-Nalewaja. The First Order Truth Behind Undecidability of Regular Path Queries Determinacy. In 22nd International Conference on Database Theory (ICDT 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 127, pp. 15:1-15:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


Copy BibTex To Clipboard

@InProceedings{gluch_et_al:LIPIcs.ICDT.2019.15,
  author =	{G{\l}uch, Grzegorz and Marcinkowski, Jerzy and Ostropolski-Nalewaja, Piotr},
  title =	{{The First Order Truth Behind Undecidability of Regular Path Queries Determinacy}},
  booktitle =	{22nd International Conference on Database Theory (ICDT 2019)},
  pages =	{15:1--15:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-101-6},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{127},
  editor =	{Barcelo, Pablo and Calautti, Marco},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2019.15},
  URN =		{urn:nbn:de:0030-drops-103175},
  doi =		{10.4230/LIPIcs.ICDT.2019.15},
  annote =	{Keywords: database theory, query, view, determinacy, recursive path queries}
}
Document
A Family of Approximation Algorithms for the Maximum Duo-Preservation String Mapping Problem

Authors: Bartlomiej Dudek, Pawel Gawrychowski, and Piotr Ostropolski-Nalewaja

Published in: LIPIcs, Volume 78, 28th Annual Symposium on Combinatorial Pattern Matching (CPM 2017)


Abstract
In the Maximum Duo-Preservation String Mapping problem we are given two strings and wish to map the letters of the former to the letters of the latter as to maximise the number of duos. A duo is a pair of consecutive letters that is mapped to a pair of consecutive letters in the same order. This is complementary to the well-studied Minimum Common String Partition problem, where the goal is to partition the former string into blocks that can be permuted and concatenated to obtain the latter string. Maximum Duo-Preservation String Mapping is APX-hard. After a series of improvements, Brubach [WABI 2016] showed a polynomial-time 3.25-approximation algorithm. Our main contribution is that, for any eps>0, there exists a polynomial-time (2+eps)-approximation algorithm. Similarly to a previous solution by Boria et al. [CPM 2016], our algorithm uses the local search technique. However, this is used only after a certain preliminary greedy procedure, which gives us more structure and makes a more general local search possible. We complement this with a specialised version of the algorithm that achieves 2.67-approximation in quadratic time.

Cite as

Bartlomiej Dudek, Pawel Gawrychowski, and Piotr Ostropolski-Nalewaja. A Family of Approximation Algorithms for the Maximum Duo-Preservation String Mapping Problem. In 28th Annual Symposium on Combinatorial Pattern Matching (CPM 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 78, pp. 10:1-10:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


Copy BibTex To Clipboard

@InProceedings{dudek_et_al:LIPIcs.CPM.2017.10,
  author =	{Dudek, Bartlomiej and Gawrychowski, Pawel and Ostropolski-Nalewaja, Piotr},
  title =	{{A Family of Approximation Algorithms for the Maximum Duo-Preservation String Mapping Problem}},
  booktitle =	{28th Annual Symposium on Combinatorial Pattern Matching (CPM 2017)},
  pages =	{10:1--10:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-039-2},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{78},
  editor =	{K\"{a}rkk\"{a}inen, Juha and Radoszewski, Jakub and Rytter, Wojciech},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CPM.2017.10},
  URN =		{urn:nbn:de:0030-drops-73458},
  doi =		{10.4230/LIPIcs.CPM.2017.10},
  annote =	{Keywords: approximation scheme, minimum common string partition, local search}
}
  • Refine by Author
  • 3 Ostropolski-Nalewaja, Piotr
  • 2 Marcinkowski, Jerzy
  • 1 Dudek, Bartlomiej
  • 1 Feller, Thomas
  • 1 Gawrychowski, Pawel
  • Show More...

  • Refine by Classification
  • 1 Information systems → Graph-based database models
  • 1 Mathematics of computing → Graph theory
  • 1 Theory of computation → Database query languages (principles)
  • 1 Theory of computation → Database theory
  • 1 Theory of computation → Description logics
  • Show More...

  • Refine by Keyword
  • 2 database theory
  • 2 determinacy
  • 2 query
  • 2 view
  • 1 TGDs
  • Show More...

  • Refine by Type
  • 4 document

  • Refine by Publication Year
  • 1 2017
  • 1 2019
  • 1 2020
  • 1 2023

Questions / Remarks / Feedback
X

Feedback for Dagstuhl Publishing


Thanks for your feedback!

Feedback submitted

Could not send message

Please try again later or send an E-mail