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Documents authored by Hannula, Miika


Document
Information Inequality Problem over Set Functions

Authors: Miika Hannula

Published in: LIPIcs, Volume 290, 27th International Conference on Database Theory (ICDT 2024)


Abstract
Information inequalities appear in many database applications such as query output size bounds, query containment, and implication between data dependencies. Recently Khamis et al. [Mahmoud Abo Khamis et al., 2020] proposed to study the algorithmic aspects of information inequalities, including the information inequality problem: decide whether a linear inequality over entropies of random variables is valid. While the decidability of this problem is a major open question, applications often involve only inequalities that adhere to specific syntactic forms linked to useful semantic invariance properties. This paper studies the information inequality problem in different syntactic and semantic scenarios that arise from database applications. Focusing on the boundary between tractability and intractability, we show that the information inequality problem is coNP-complete if restricted to normal polymatroids, and in polynomial time if relaxed to monotone functions. We also examine syntactic restrictions related to query output size bounds, and provide an alternative proof, through monotone functions, for the polynomial-time computability of the entropic bound over simple sets of degree constraints.

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Miika Hannula. Information Inequality Problem over Set Functions. In 27th International Conference on Database Theory (ICDT 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 290, pp. 19:1-19:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)


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@InProceedings{hannula:LIPIcs.ICDT.2024.19,
  author =	{Hannula, Miika},
  title =	{{Information Inequality Problem over Set Functions}},
  booktitle =	{27th International Conference on Database Theory (ICDT 2024)},
  pages =	{19:1--19:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-312-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{290},
  editor =	{Cormode, Graham and Shekelyan, Michael},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2024.19},
  URN =		{urn:nbn:de:0030-drops-198011},
  doi =		{10.4230/LIPIcs.ICDT.2024.19},
  annote =	{Keywords: entropy, information theory, worst-case output size, computational complexity}
}
Document
Conditional Independence on Semiring Relations

Authors: Miika Hannula

Published in: LIPIcs, Volume 290, 27th International Conference on Database Theory (ICDT 2024)


Abstract
Conditional independence plays a foundational role in database theory, probability theory, information theory, and graphical models. In databases, a notion similar to conditional independence, known as the (embedded) multivalued dependency, appears in database normalization. Many properties of conditional independence are shared across various domains, and to some extent these commonalities can be studied through a measure-theoretic approach. The present paper proposes an alternative approach via semiring relations, defined by extending database relations with tuple annotations from some commutative semiring. Integrating various interpretations of conditional independence in this context, we investigate how the choice of the underlying semiring impacts the corresponding axiomatic and decomposition properties. We specifically identify positivity and multiplicative cancellativity as the key semiring properties that enable extending results from the relational context to the broader semiring framework. Additionally, we explore the relationships between different conditional independence notions through model theory.

Cite as

Miika Hannula. Conditional Independence on Semiring Relations. In 27th International Conference on Database Theory (ICDT 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 290, pp. 20:1-20:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)


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@InProceedings{hannula:LIPIcs.ICDT.2024.20,
  author =	{Hannula, Miika},
  title =	{{Conditional Independence on Semiring Relations}},
  booktitle =	{27th International Conference on Database Theory (ICDT 2024)},
  pages =	{20:1--20:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-312-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{290},
  editor =	{Cormode, Graham and Shekelyan, Michael},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2024.20},
  URN =		{urn:nbn:de:0030-drops-198023},
  doi =		{10.4230/LIPIcs.ICDT.2024.20},
  annote =	{Keywords: semiring, conditional independence, functional dependency, decomposition, axiom}
}
Document
On the Complexity of Horn and Krom Fragments of Second-Order Boolean Logic

Authors: Miika Hannula, Juha Kontinen, Martin Lück, and Jonni Virtema

Published in: LIPIcs, Volume 183, 29th EACSL Annual Conference on Computer Science Logic (CSL 2021)


Abstract
Second-order Boolean logic is a generalization of QBF, whose constant alternation fragments are known to be complete for the levels of the exponential time hierarchy. We consider two types of restriction of this logic: 1) restrictions to term constructions, 2) restrictions to the form of the Boolean matrix. Of the first sort, we consider two kinds of restrictions: firstly, disallowing nested use of proper function variables, and secondly stipulating that each function variable must appear with a fixed sequence of arguments. Of the second sort, we consider Horn, Krom, and core fragments of the Boolean matrix. We classify the complexity of logics obtained by combining these two types of restrictions. We show that, in most cases, logics with k alternating blocks of function quantifiers are complete for the kth or (k-1)th level of the exponential time hierarchy. Furthermore, we establish NL-completeness for the Krom and core fragments, when k = 1 and both restrictions of the first sort are in effect.

Cite as

Miika Hannula, Juha Kontinen, Martin Lück, and Jonni Virtema. On the Complexity of Horn and Krom Fragments of Second-Order Boolean Logic. In 29th EACSL Annual Conference on Computer Science Logic (CSL 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 183, pp. 27:1-27:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)


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@InProceedings{hannula_et_al:LIPIcs.CSL.2021.27,
  author =	{Hannula, Miika and Kontinen, Juha and L\"{u}ck, Martin and Virtema, Jonni},
  title =	{{On the Complexity of Horn and Krom Fragments of Second-Order Boolean Logic}},
  booktitle =	{29th EACSL Annual Conference on Computer Science Logic (CSL 2021)},
  pages =	{27:1--27:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-175-7},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{183},
  editor =	{Baier, Christel and Goubault-Larrecq, Jean},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2021.27},
  URN =		{urn:nbn:de:0030-drops-134610},
  doi =		{10.4230/LIPIcs.CSL.2021.27},
  annote =	{Keywords: quantified Boolean formulae, computational complexity, second-order logic, Horn and Krom fragment}
}
Document
Validity and Entailment in Modal and Propositional Dependence Logics

Authors: Miika Hannula

Published in: LIPIcs, Volume 82, 26th EACSL Annual Conference on Computer Science Logic (CSL 2017)


Abstract
The computational properties of modal and propositional dependence logics have been extensively studied over the past few years, starting from a result by Sevenster showing NEXPTIME-completeness of the satisfiability problem for modal dependence logic. Thus far, however, the validity and entailment properties of these logics have remained uncharacterised to a great extent. This paper establishes a complete classification of the complexity of validity and entailment in modal and propositional dependence logics. In particular, we address the question of the complexity of validity in modal dependence logic. By showing that it is NEXPTIME-complete we refute an earlier conjecture proposing a higher complexity for the problem.

Cite as

Miika Hannula. Validity and Entailment in Modal and Propositional Dependence Logics. In 26th EACSL Annual Conference on Computer Science Logic (CSL 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 82, pp. 28:1-28:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{hannula:LIPIcs.CSL.2017.28,
  author =	{Hannula, Miika},
  title =	{{Validity and Entailment in Modal and Propositional Dependence Logics}},
  booktitle =	{26th EACSL Annual Conference on Computer Science Logic (CSL 2017)},
  pages =	{28:1--28:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-045-3},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{82},
  editor =	{Goranko, Valentin and Dam, Mads},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2017.28},
  URN =		{urn:nbn:de:0030-drops-76691},
  doi =		{10.4230/LIPIcs.CSL.2017.28},
  annote =	{Keywords: modal logic, propositional logic, dependence logic, entailment, validity, complexity}
}
Document
Hierarchies in independence logic

Authors: Pietro Galliani, Miika Hannula, and Juha Kontinen

Published in: LIPIcs, Volume 23, Computer Science Logic 2013 (CSL 2013)


Abstract
We study the expressive power of fragments of inclusion and independence logic defined either by restricting the number of universal quantifiers or the arity of inclusion and independence atoms in formulas. Assuming the so-called lax semantics for these logics, we relate these fragments of inclusion and independence logic to familiar sublogics of existential second-order logic. We also show that, with respect to the stronger strict semantics, inclusion logic is equivalent to existential second-order logic.

Cite as

Pietro Galliani, Miika Hannula, and Juha Kontinen. Hierarchies in independence logic. In Computer Science Logic 2013 (CSL 2013). Leibniz International Proceedings in Informatics (LIPIcs), Volume 23, pp. 263-280, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


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@InProceedings{galliani_et_al:LIPIcs.CSL.2013.263,
  author =	{Galliani, Pietro and Hannula, Miika and Kontinen, Juha},
  title =	{{Hierarchies in independence logic}},
  booktitle =	{Computer Science Logic 2013 (CSL 2013)},
  pages =	{263--280},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-60-6},
  ISSN =	{1868-8969},
  year =	{2013},
  volume =	{23},
  editor =	{Ronchi Della Rocca, Simona},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2013.263},
  URN =		{urn:nbn:de:0030-drops-42021},
  doi =		{10.4230/LIPIcs.CSL.2013.263},
  annote =	{Keywords: Existential second-order logic, Independence logic, Inclusion logic, Expressiveness hierarchies}
}
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