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Documents authored by Bertossi, Leopoldo


Document
The Shapley Value of Tuples in Query Answering

Authors: Ester Livshits, Leopoldo Bertossi, Benny Kimelfeld, and Moshe Sebag

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


Abstract
We investigate the application of the Shapley value to quantifying the contribution of a tuple to a query answer. The Shapley value is a widely known numerical measure in cooperative game theory and in many applications of game theory for assessing the contribution of a player to a coalition game. It has been established already in the 1950s, and is theoretically justified by being the very single wealth-distribution measure that satisfies some natural axioms. While this value has been investigated in several areas, it received little attention in data management. We study this measure in the context of conjunctive and aggregate queries by defining corresponding coalition games. We provide algorithmic and complexity-theoretic results on the computation of Shapley-based contributions to query answers; and for the hard cases we present approximation algorithms.

Cite as

Ester Livshits, Leopoldo Bertossi, Benny Kimelfeld, and Moshe Sebag. The Shapley Value of Tuples in Query Answering. In 23rd International Conference on Database Theory (ICDT 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 155, pp. 20:1-20:19, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)


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@InProceedings{livshits_et_al:LIPIcs.ICDT.2020.20,
  author =	{Livshits, Ester and Bertossi, Leopoldo and Kimelfeld, Benny and Sebag, Moshe},
  title =	{{The Shapley Value of Tuples in Query Answering}},
  booktitle =	{23rd International Conference on Database Theory (ICDT 2020)},
  pages =	{20:1--20:19},
  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.2020.20},
  URN =		{urn:nbn:de:0030-drops-119442},
  doi =		{10.4230/LIPIcs.ICDT.2020.20},
  annote =	{Keywords: Shapley value, query answering, conjunctive queries, aggregate queries}
}
Document
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)


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@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
From Causes for Database Queries to Repairs and Model-Based Diagnosis and Back

Authors: Babak Salimi and Leopoldo Bertossi

Published in: LIPIcs, Volume 31, 18th International Conference on Database Theory (ICDT 2015)


Abstract
In this work we establish and investigate connections between causality for query answers in databases, database repairs wrt. denial constraints, and consistency-based diagnosis. The first two are relatively new problems in databases, and the third one is an established subject in knowledge representation. We show how to obtain database repairs from causes and the other way around. Causality problems are formulated as diagnosis problems, and the diagnoses provide causes and their responsibilities. The vast body of research on database repairs can be applied to the newer problem of determining actual causes for query answers and their responsibilities. These connections, which are interesting per se, allow us, after a transition-inspired by consistency-based diagnosis- to computational problems on hitting sets and vertex covers in hypergraphs, to obtain several new algorithmic and complexity results for database causality.

Cite as

Babak Salimi and Leopoldo Bertossi. From Causes for Database Queries to Repairs and Model-Based Diagnosis and Back. In 18th International Conference on Database Theory (ICDT 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 31, pp. 342-362, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2015)


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@InProceedings{salimi_et_al:LIPIcs.ICDT.2015.342,
  author =	{Salimi, Babak and Bertossi, Leopoldo},
  title =	{{From Causes for Database Queries to Repairs and Model-Based Diagnosis and Back}},
  booktitle =	{18th International Conference on Database Theory (ICDT 2015)},
  pages =	{342--362},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-79-8},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{31},
  editor =	{Arenas, Marcelo and Ugarte, Mart{\'\i}n},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2015.342},
  URN =		{urn:nbn:de:0030-drops-49948},
  doi =		{10.4230/LIPIcs.ICDT.2015.342},
  annote =	{Keywords: causality,diagnosis,repairs,consistent query answering,integrity constraints}
}
Document
Inconsistency Tolerance (Dagstuhl Seminar 03241)

Authors: Leopoldo Bertossi, Philippe Besnard, Anthony Hunter, and Torsten Schaub

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


Abstract

Cite as

Leopoldo Bertossi, Philippe Besnard, Anthony Hunter, and Torsten Schaub. Inconsistency Tolerance (Dagstuhl Seminar 03241). Dagstuhl Seminar Report 382, pp. 1-8, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2003)


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@TechReport{bertossi_et_al:DagSemRep.382,
  author =	{Bertossi, Leopoldo and Besnard, Philippe and Hunter, Anthony and Schaub, Torsten},
  title =	{{Inconsistency Tolerance (Dagstuhl Seminar 03241)}},
  pages =	{1--8},
  ISSN =	{1619-0203},
  year =	{2003},
  type = 	{Dagstuhl Seminar Report},
  number =	{382},
  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.382},
  URN =		{urn:nbn:de:0030-drops-152624},
  doi =		{10.4230/DagSemRep.382},
}
Document
Semantics in Databases (Dagstuhl Seminar 01021)

Authors: Leopoldo Bertossi, Gyula O. H. Katona, Klaus-Dieter Schewe, and Bernhard Thalheim

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


Abstract

Cite as

Leopoldo Bertossi, Gyula O. H. Katona, Klaus-Dieter Schewe, and Bernhard Thalheim. Semantics in Databases (Dagstuhl Seminar 01021). Dagstuhl Seminar Report 295, pp. 1-24, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2001)


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@TechReport{bertossi_et_al:DagSemRep.295,
  author =	{Bertossi, Leopoldo and Katona, Gyula O. H. and Schewe, Klaus-Dieter and Thalheim, Bernhard},
  title =	{{Semantics in Databases (Dagstuhl Seminar 01021)}},
  pages =	{1--24},
  ISSN =	{1619-0203},
  year =	{2001},
  type = 	{Dagstuhl Seminar Report},
  number =	{295},
  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.295},
  URN =		{urn:nbn:de:0030-drops-151795},
  doi =		{10.4230/DagSemRep.295},
}
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