Search Results

Documents authored by Gottlob, Georg

Document
DOI: 10.4230/LIPIcs.ICDT.2026.21
First-Order Rewritability of Rule-Based Ontology Mediated Queries with Negation

Authors: Georg Gottlob, Marco Manna, Andreas Pieris, and Aldo Ricioppo

Published in: LIPIcs, Volume 365, 29th International Conference on Database Theory (ICDT 2026)

Abstract
The idea of using an ontology to enrich user queries with domain knowledge has attracted considerable attention from the database and KR communities during the last fifteen years or so. The ontology and the user query can be conveniently seen as two components of one composite query, called ontology-mediated query (omq), while an omq language (OL,QL) collects all such omqs where the ontology is expressed using the ontology language OL and the user query comes from the query language QL. The evaluation problem for rule-based omq languages of the form (OL,CQ), where OL is a rule-based ontology language, i.e., it collects ontologies modelled using tuple-generating dependencies (a.k.a. existential rules), and CQ is the language of conjunctive queries, has been extensively studied in the literature. In particular, the notion of first-order rewritability of such languages, i.e., the property of being able to rewrite every omq from the language in question to an equivalent first-order query, has been studied in depth. This research effort led an algorithmic characterization of when a rule-based omq language (OL,CQ) is first-order rewritable. More precisely, there is a uniform algorithm Rewrite such that, for every rule-based ontology language OL, the omq language (OL,CQ) is first-order rewritable iff for every omq O from (OL,CQ), the algorithm Rewrite on input O terminates and constructs a first-order rewriting of O. The question that we are interested in is whether the above algorithmic characterization can be extended to rule-based omq languages of the form (OL,nCQ), where nCQ is the language of conjunctive queries with the useful feature of negation. The goal of this work is to initiate effort towards the settlement of the above highly non-trivial question. To this end, we provide a new algorithm, which is a non-trivial extension of the algorithm Rewrite for positive omqs, and show the following: under the Skolem semantics, a well-established approach for defining the answer to a rule-based omq when the user query can use negation, the proposed algorithm is a first-order rewriter for (OL,nCQ), where OL is the language of linear or acyclic tuple-generating dependencies, two central rule-based ontology languages that ensure first-order rewritability for positive omqs. We strongly believe that the new algorithm can serve as a good starting point towards the full settlement of our main question.
Cite as

Georg Gottlob, Marco Manna, Andreas Pieris, and Aldo Ricioppo. First-Order Rewritability of Rule-Based Ontology Mediated Queries with Negation. In 29th International Conference on Database Theory (ICDT 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 365, pp. 21:1-21:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

Copy BibTex To Clipboard

@InProceedings{gottlob_et_al:LIPIcs.ICDT.2026.21,
  author =	{Gottlob, Georg and Manna, Marco and Pieris, Andreas and Ricioppo, Aldo},
  title =	{{First-Order Rewritability of Rule-Based Ontology Mediated Queries with Negation}},
  booktitle =	{29th International Conference on Database Theory (ICDT 2026)},
  pages =	{21:1--21:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-413-0},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{365},
  editor =	{ten Cate, Balder and Funk, Maurice},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2026.21},
  URN =		{urn:nbn:de:0030-drops-256353},
  doi =		{10.4230/LIPIcs.ICDT.2026.21},
  annote =	{Keywords: ontology-mediated queries, tuple-generating dependencies, conjunctive queries with negation, first-order rewritability}
}
Document
Invited Talk
DOI: 10.4230/LIPIcs.CSL.2024.3
Artificial Intelligence and Artificial Ignorance (Invited Talk)

Authors: Georg Gottlob

Published in: LIPIcs, Volume 288, 32nd EACSL Annual Conference on Computer Science Logic (CSL 2024)

Abstract
This invited talk first delves into the division between the two primary branches of AI research: symbolic AI, which predominantly focuses on knowledge representation and logical reasoning, and sub-symbolic AI, primarily centered on machine learning employing neural networks. We explore both the notable accomplishments and the challenges encountered in each of these approaches. We provide instances where traditional deep learning encounters limitations, and we elucidate significant obstacles in achieving automated symbolic reasoning. We then discuss the recent groundbreaking advancements in generative AI, driven by language models such as ChatGPT. We showcase instances where these models excel and, conversely, where they exhibit shortcomings and produce erroneous information. We identify and illustrate five key reasons for potential failures in language models, which include: [(i)] 1) information loss due to data compression, 2) training bias, 3) the incorporation of incorrect external data, 4) the misordering of results, and 5) the failure to detect and resolve logical inconsistencies contained in a sequence of LLM-generated prompt-answers. Lastly, we touch upon the Chat2Data project, which endeavors to leverage language models for the automated verification and enhancement of relational databases, all while mitigating the pitfalls (i)-(v) mentioned earlier.
Cite as

Georg Gottlob. Artificial Intelligence and Artificial Ignorance (Invited Talk). In 32nd EACSL Annual Conference on Computer Science Logic (CSL 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 288, p. 3:1, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

Copy BibTex To Clipboard

@InProceedings{gottlob:LIPIcs.CSL.2024.3,
  author =	{Gottlob, Georg},
  title =	{{Artificial Intelligence and Artificial Ignorance}},
  booktitle =	{32nd EACSL Annual Conference on Computer Science Logic (CSL 2024)},
  pages =	{3:1--3:1},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-310-2},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{288},
  editor =	{Murano, Aniello and Silva, Alexandra},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2024.3},
  URN =		{urn:nbn:de:0030-drops-196459},
  doi =		{10.4230/LIPIcs.CSL.2024.3},
  annote =	{Keywords: AI applications, symbolic AI, sub-symbolic AI, AI usefulness, achievements of symbolic AI, achievements of machine learning, machine learning errors and mistakes, large language models, LLMs, LLM usefulness, LLM mistakes, inaccuracies}
}
Document
DOI: 10.4230/LIPIcs.MFCS.2020.41
Fractional Covers of Hypergraphs with Bounded Multi-Intersection

Authors: Georg Gottlob, Matthias Lanzinger, Reinhard Pichler, and Igor Razgon

Published in: LIPIcs, Volume 170, 45th International Symposium on Mathematical Foundations of Computer Science (MFCS 2020)

Abstract
Fractional (hyper-)graph theory is concerned with the specific problems that arise when fractional analogues of otherwise integer-valued (hyper-)graph invariants are considered. The focus of this paper is on fractional edge covers of hypergraphs. Our main technical result generalizes and unifies previous conditions under which the size of the support of fractional edge covers is bounded independently of the size of the hypergraph itself. This allows us to extend previous tractability results for checking if the fractional hypertree width of a given hypergraph is ≤ k for some constant k. We also show how our results translate to fractional vertex covers.
Cite as

Georg Gottlob, Matthias Lanzinger, Reinhard Pichler, and Igor Razgon. Fractional Covers of Hypergraphs with Bounded Multi-Intersection. In 45th International Symposium on Mathematical Foundations of Computer Science (MFCS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 170, pp. 41:1-41:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

Copy BibTex To Clipboard

@InProceedings{gottlob_et_al:LIPIcs.MFCS.2020.41,
  author =	{Gottlob, Georg and Lanzinger, Matthias and Pichler, Reinhard and Razgon, Igor},
  title =	{{Fractional Covers of Hypergraphs with Bounded Multi-Intersection}},
  booktitle =	{45th International Symposium on Mathematical Foundations of Computer Science (MFCS 2020)},
  pages =	{41:1--41:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-159-7},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{170},
  editor =	{Esparza, Javier and Kr\'{a}l', Daniel},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2020.41},
  URN =		{urn:nbn:de:0030-drops-127317},
  doi =		{10.4230/LIPIcs.MFCS.2020.41},
  annote =	{Keywords: Fractional graph theory, fractional edge cover, fractional hypertree width, bounded multi-intersection, fractional cover, fractional vertex cover}
}
Document
DOI: 10.4230/LIPIcs.ICDT.2019.16
Datalog: Bag Semantics via Set Semantics

Authors: Leopoldo Bertossi, Georg Gottlob, and Reinhard Pichler

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

Abstract
Duplicates in data management are common and problematic. In this work, we present a translation of Datalog under bag semantics into a well-behaved extension of Datalog, the so-called warded Datalog^+/-, under set semantics. From a theoretical point of view, this allows us to reason on bag semantics by making use of the well-established theoretical foundations of set semantics. From a practical point of view, this allows us to handle the bag semantics of Datalog by powerful, existing query engines for the required extension of Datalog. This use of Datalog^+/- is extended to give a set semantics to duplicates in Datalog^+/- itself. We investigate the properties of the resulting Datalog^+/- programs, the problem of deciding multiplicities, and expressibility of some bag operations. Moreover, the proposed translation has the potential for interesting applications such as to Multiset Relational Algebra and the semantic web query language SPARQL with bag semantics.
Cite as

Leopoldo Bertossi, Georg Gottlob, and Reinhard Pichler. Datalog: Bag Semantics via Set Semantics. In 22nd International Conference on Database Theory (ICDT 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 127, pp. 16:1-16:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

Copy BibTex To Clipboard

@InProceedings{bertossi_et_al:LIPIcs.ICDT.2019.16,
  author =	{Bertossi, Leopoldo and Gottlob, Georg and Pichler, Reinhard},
  title =	{{Datalog: Bag Semantics via Set Semantics}},
  booktitle =	{22nd International Conference on Database Theory (ICDT 2019)},
  pages =	{16:1--16:19},
  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.2019.16},
  URN =		{urn:nbn:de:0030-drops-103188},
  doi =		{10.4230/LIPIcs.ICDT.2019.16},
  annote =	{Keywords: Datalog, duplicates, multisets, query answering, chase, Datalog+/-}
}
Document
DOI: 10.4230/LIPIcs.ICDT.2016.1
The ICDT 2016 Test of Time Award Announcement

Authors: Foto N. Afrati, Claire David, and Georg Gottlob

Published in: LIPIcs, Volume 48, 19th International Conference on Database Theory (ICDT 2016)

Abstract
We describe the 2016 ICDT Test of Time Award which is awarded to Chandra Chekuri and Anand Rajaraman for their 1997 ICDT paper on "Conjunctive Query Containment Revisited".
Cite as

Foto N. Afrati, Claire David, and Georg Gottlob. The ICDT 2016 Test of Time Award Announcement. In 19th International Conference on Database Theory (ICDT 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 48, pp. 1:1-1:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

Copy BibTex To Clipboard

@InProceedings{afrati_et_al:LIPIcs.ICDT.2016.1,
  author =	{Afrati, Foto N. and David, Claire and Gottlob, Georg},
  title =	{{The ICDT 2016 Test of Time Award Announcement}},
  booktitle =	{19th International Conference on Database Theory (ICDT 2016)},
  pages =	{1:1--1:2},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-002-6},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{48},
  editor =	{Martens, Wim and Zeume, Thomas},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2016.1},
  URN =		{urn:nbn:de:0030-drops-57938},
  doi =		{10.4230/LIPIcs.ICDT.2016.1},
  annote =	{Keywords: conjunctive query, treewidth, NP-hardness, rewriting}
}
Document
DOI: 10.4230/DagRep.1.8.96
Computer Science & Problem Solving: New Foundations (Dagstuhl Seminar 11351)

Authors: Iris van Rooij, Yll Haxhimusa, Zygmunt Pizlo, and Georg Gottlob

Published in: Dagstuhl Reports, Volume 1, Issue 8 (2011)

Abstract
This report documents the program and the outcomes of Dagstuhl Seminar 11351 ``Computer Science & Problem Solving: New Foundations''. This seminar was the first Dagstuhl seminar that brought together a balanced group of computer scientists and psychologists to exchange perspectives on problem solving. In the 1950s the seminal work of Allen Newell and Herbert Simon laid the theoretical foundations for problem solving research as we know it today, but the field had since become disconnected from contemporary computer science. The aim of this seminar was to promote theoretical progress in problem solving research by renewing the connection between psychology and computer science in this area.
Cite as

Iris van Rooij, Yll Haxhimusa, Zygmunt Pizlo, and Georg Gottlob. Computer Science & Problem Solving: New Foundations (Dagstuhl Seminar 11351). In Dagstuhl Reports, Volume 1, Issue 8, pp. 96-124, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

Copy BibTex To Clipboard

@Article{vanrooij_et_al:DagRep.1.8.96,
  author =	{van Rooij, Iris and Haxhimusa, Yll and Pizlo, Zygmunt and Gottlob, Georg},
  title =	{{Computer Science \& Problem Solving: New Foundations (Dagstuhl Seminar 11351)}},
  pages =	{96--124},
  journal =	{Dagstuhl Reports},
  ISSN =	{2192-5283},
  year =	{2011},
  volume =	{1},
  number =	{8},
  editor =	{van Rooij, Iris and Haxhimusa, Yll and Pizlo, Zygmunt and Gottlob, Georg},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagRep.1.8.96},
  URN =		{urn:nbn:de:0030-drops-33169},
  doi =		{10.4230/DagRep.1.8.96},
  annote =	{Keywords: Problem solving, Cognitive psychology, Cognitive systems, Vision Representations, Computational complexity}
}
Document
DOI: 10.4230/LIPIcs.STACS.2011.12
Structural Decomposition Methods and What They are Good For

Authors: Markus Aschinger, Conrad Drescher, Georg Gottlob, Peter Jeavons, and Evgenij Thorstensen

Published in: LIPIcs, Volume 9, 28th International Symposium on Theoretical Aspects of Computer Science (STACS 2011)

Abstract
This paper reviews structural problem decomposition methods, such as tree and path decompositions. It is argued that these notions can be applied in two distinct ways: Either to show that a problem is efficiently solvable when a width parameter is fixed, or to prove that the unrestricted (or some width-parameter free) version of a problem is tractable by using a width-notion as a mathematical tool for directly solving the problem at hand. Examples are given for both cases. As a new showcase for the latter usage, we report some recent results on the Partner Units Problem, a form of configuration problem arising in an industrial context. We use the notion of a path decomposition to identify and solve a tractable class of instances of this problem with practical relevance.
Cite as

Markus Aschinger, Conrad Drescher, Georg Gottlob, Peter Jeavons, and Evgenij Thorstensen. Structural Decomposition Methods and What They are Good For. In 28th International Symposium on Theoretical Aspects of Computer Science (STACS 2011). Leibniz International Proceedings in Informatics (LIPIcs), Volume 9, pp. 12-28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2011)

Copy BibTex To Clipboard

@InProceedings{aschinger_et_al:LIPIcs.STACS.2011.12,
  author =	{Aschinger, Markus and Drescher, Conrad and Gottlob, Georg and Jeavons, Peter and Thorstensen, Evgenij},
  title =	{{Structural Decomposition Methods and What They are Good For}},
  booktitle =	{28th International Symposium on Theoretical Aspects of Computer Science (STACS 2011)},
  pages =	{12--28},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-25-5},
  ISSN =	{1868-8969},
  year =	{2011},
  volume =	{9},
  editor =	{Schwentick, Thomas and D\"{u}rr, Christoph},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2011.12},
  URN =		{urn:nbn:de:0030-drops-29960},
  doi =		{10.4230/LIPIcs.STACS.2011.12},
  annote =	{Keywords: decompositions}
}
Document
DOI: 10.4230/DagSemRep.253
Finite Model Theory, Databases, and Computer-Aided Verification (Dagstuhl Seminar 99401)

Authors: Georg Gottlob, Erich Grädel, Moshe Vardi, and Victor Vianu

Published in: Dagstuhl Seminar Reports. Dagstuhl Seminar Reports, Volume 1 (2021)

Abstract
Cite as

Georg Gottlob, Erich Grädel, Moshe Vardi, and Victor Vianu. Finite Model Theory, Databases, and Computer-Aided Verification (Dagstuhl Seminar 99401). Dagstuhl Seminar Report 253, pp. 1-25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2000)

Copy BibTex To Clipboard

@TechReport{gottlob_et_al:DagSemRep.253,
  author =	{Gottlob, Georg and Gr\"{a}del, Erich and Vardi, Moshe and Vianu, Victor},
  title =	{{Finite Model Theory, Databases, and Computer-Aided Verification (Dagstuhl Seminar 99401)}},
  pages =	{1--25},
  ISSN =	{1619-0203},
  year =	{2000},
  type = 	{Dagstuhl Seminar Report},
  number =	{253},
  institution =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagSemRep.253},
  URN =		{urn:nbn:de:0030-drops-151399},
  doi =		{10.4230/DagSemRep.253},
}
Any Issues?
X

Feedback on the Current Page

CAPTCHA

Thanks for your feedback!

Feedback submitted to Dagstuhl Publishing

Could not send message

Please try again later or send an E-mail
© 2023-2026 Schloss Dagstuhl – LZI GmbH Schloss Dagstuhl – LZI GmbH About DROPS Imprint Privacy Contact