65 Search Results for "Weil, Pascal"


Volume

LIPIcs, Volume 1

25th International Symposium on Theoretical Aspects of Computer Science

STACS 2008, February 21-23, 2008, Bordeaux, France

Editors: Susanne Albers and Pascal Weil

Document
Propositional Dynamic Logic and Asynchronous Cascade Decompositions for Regular Trace Languages

Authors: Bharat Adsul, Paul Gastin, Saptarshi Sarkar, and Pascal Weil

Published in: LIPIcs, Volume 243, 33rd International Conference on Concurrency Theory (CONCUR 2022)


Abstract
One of the main motivations for this work is to obtain a distributed Krohn-Rhodes theorem for Mazurkiewicz traces. Concretely, we focus on the recently introduced operation of local cascade product of asynchronous automata and ask if every regular trace language can be accepted by a local cascade product of "simple" asynchronous automata. Our approach crucially relies on the development of a local and past-oriented propositional dynamic logic (LocPastPDL) over traces which is shown to be expressively complete with respect to all regular trace languages. An event-formula of LocPastPDL allows to reason about the causal past of an event and a path-formula of LocPastPDL, localized at a process, allows to march along the sequence of past-events in which that process participates, checking for local regular patterns interspersed with local tests of other event-formulas. We also use additional constant formulas to compare the leading process events from the causal past. The new logic LocPastPDL is of independent interest, and the proof of its expressive completeness is rather subtle. Finally, we provide a translation of LocPastPDL formulas into local cascade products. More precisely, we show that every LocPastPDL formula can be computed by a restricted local cascade product of the gossip automaton and localized 2-state asynchronous reset automata and localized asynchronous permutation automata.

Cite as

Bharat Adsul, Paul Gastin, Saptarshi Sarkar, and Pascal Weil. Propositional Dynamic Logic and Asynchronous Cascade Decompositions for Regular Trace Languages. In 33rd International Conference on Concurrency Theory (CONCUR 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 243, pp. 28:1-28:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


Copy BibTex To Clipboard

@InProceedings{adsul_et_al:LIPIcs.CONCUR.2022.28,
  author =	{Adsul, Bharat and Gastin, Paul and Sarkar, Saptarshi and Weil, Pascal},
  title =	{{Propositional Dynamic Logic and Asynchronous Cascade Decompositions for Regular Trace Languages}},
  booktitle =	{33rd International Conference on Concurrency Theory (CONCUR 2022)},
  pages =	{28:1--28:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-246-4},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{243},
  editor =	{Klin, Bartek and Lasota, S{\l}awomir and Muscholl, Anca},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2022.28},
  URN =		{urn:nbn:de:0030-drops-170915},
  doi =		{10.4230/LIPIcs.CONCUR.2022.28},
  annote =	{Keywords: Mazurkiewicz traces, propositional dynamic logic, regular trace languages, asynchronous automata, cascade product, Krohn Rhodes theorem}
}
Document
Wreath/Cascade Products and Related Decomposition Results for the Concurrent Setting of Mazurkiewicz Traces

Authors: Bharat Adsul, Paul Gastin, Saptarshi Sarkar, and Pascal Weil

Published in: LIPIcs, Volume 171, 31st International Conference on Concurrency Theory (CONCUR 2020)


Abstract
We develop a new algebraic framework to reason about languages of Mazurkiewicz traces. This framework supports true concurrency and provides a non-trivial generalization of the wreath product operation to the trace setting. A novel local wreath product principle has been established. The new framework is crucially used to propose a decomposition result for recognizable trace languages, which is an analogue of the Krohn-Rhodes theorem. We prove this decomposition result in the special case of acyclic architectures and apply it to extend Kamp’s theorem to this setting. We also introduce and analyze distributed automata-theoretic operations called local and global cascade products. Finally, we show that aperiodic trace languages can be characterized using global cascade products of localized and distributed two-state reset automata.

Cite as

Bharat Adsul, Paul Gastin, Saptarshi Sarkar, and Pascal Weil. Wreath/Cascade Products and Related Decomposition Results for the Concurrent Setting of Mazurkiewicz Traces. In 31st International Conference on Concurrency Theory (CONCUR 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 171, pp. 19:1-19:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


Copy BibTex To Clipboard

@InProceedings{adsul_et_al:LIPIcs.CONCUR.2020.19,
  author =	{Adsul, Bharat and Gastin, Paul and Sarkar, Saptarshi and Weil, Pascal},
  title =	{{Wreath/Cascade Products and Related Decomposition Results for the Concurrent Setting of Mazurkiewicz Traces}},
  booktitle =	{31st International Conference on Concurrency Theory (CONCUR 2020)},
  pages =	{19:1--19:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-160-3},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{171},
  editor =	{Konnov, Igor and Kov\'{a}cs, Laura},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2020.19},
  URN =		{urn:nbn:de:0030-drops-128319},
  doi =		{10.4230/LIPIcs.CONCUR.2020.19},
  annote =	{Keywords: Mazurkiewicz traces, asynchronous automata, wreath product, cascade product, Krohn Rhodes decomposition theorem, local temporal logic over traces}
}
Document
The Quantifier Alternation Hierarchy of Synchronous Relations

Authors: Diego Figueira, Varun Ramanathan, and Pascal Weil

Published in: LIPIcs, Volume 138, 44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019)


Abstract
The class of synchronous relations, also known as automatic or regular, is one of the most studied subclasses of rational relations. It enjoys many desirable closure properties and is known to be logically characterized: the synchronous relations are exactly those that are defined by a first-order formula on the structure of all finite words, with the prefix, equal-length and last-letter predicates. Here, we study the quantifier alternation hierarchy of this logic. We show that it collapses at level Sigma_3 and that all levels below admit decidable characterizations. Our results reveal the connections between this hierarchy and the well-known hierarchy of first-order defined languages of finite words.

Cite as

Diego Figueira, Varun Ramanathan, and Pascal Weil. The Quantifier Alternation Hierarchy of Synchronous Relations. In 44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 138, pp. 29:1-29:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


Copy BibTex To Clipboard

@InProceedings{figueira_et_al:LIPIcs.MFCS.2019.29,
  author =	{Figueira, Diego and Ramanathan, Varun and Weil, Pascal},
  title =	{{The Quantifier Alternation Hierarchy of Synchronous Relations}},
  booktitle =	{44th International Symposium on Mathematical Foundations of Computer Science (MFCS 2019)},
  pages =	{29:1--29:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-117-7},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{138},
  editor =	{Rossmanith, Peter and Heggernes, Pinar and Katoen, Joost-Pieter},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2019.29},
  URN =		{urn:nbn:de:0030-drops-109735},
  doi =		{10.4230/LIPIcs.MFCS.2019.29},
  annote =	{Keywords: synchronous relations, automatic relations, first-order logic, characterization, quantifier alternation}
}
Document
Complete Volume
LIPIcs, Volume 1, STACS'08, Complete Volume

Authors: Susanne Albers and Pascal Weil

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
LIPIcs, Volume 1, STACS'08, Complete Volume

Cite as

25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


Copy BibTex To Clipboard

@Proceedings{albers_et_al:LIPIcs.STACS.2008,
  title =	{{LIPIcs, Volume 1, STACS'08, Complete Volume}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2013},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008},
  URN =		{urn:nbn:de:0030-drops-40958},
  doi =		{10.4230/LIPIcs.STACS.2008},
  annote =	{Keywords: LIPIcs, Volume 1, STACS'08, Complete Volume}
}
Document
The FO2 alternation hierarchy is decidable

Authors: Manfred Kufleitner and Pascal Weil

Published in: LIPIcs, Volume 16, Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL (2012)


Abstract
We consider the two-variable fragment FO2[<] of first-order logic over finite words. Numerous characterizations of this class are known. Therien and Wilke have shown that it is decidable whether a given regular language is definable in FO2[<]. From a practical point of view, as shown by Weis, FO2[<] is interesting since its satisfiability problem is in NP. Restricting the number of quantifier alternations yields an infinite hierarchy inside the class of FO2[<]-definable languages. We show that each level of this hierarchy is decidable. For this purpose, we relate each level of the hierarchy with a decidable variety of finite monoids. Our result implies that there are many different ways of climbing up the FO2[<]-quantifier alternation hierarchy: deterministic and co-deterministic products, Mal'cev products with definite and reverse definite semigroups, iterated block products with J-trivial monoids, and some inductively defined omega-term identities. A combinatorial tool in the process of ascension is that of condensed rankers, a refinement of the rankers of Weis and Immerman and the turtle programs of Schwentick, Therien, and Vollmer.

Cite as

Manfred Kufleitner and Pascal Weil. The FO2 alternation hierarchy is decidable. In Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL. Leibniz International Proceedings in Informatics (LIPIcs), Volume 16, pp. 426-439, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)


Copy BibTex To Clipboard

@InProceedings{kufleitner_et_al:LIPIcs.CSL.2012.426,
  author =	{Kufleitner, Manfred and Weil, Pascal},
  title =	{{The FO2 alternation hierarchy is decidable}},
  booktitle =	{Computer Science Logic (CSL'12) - 26th International Workshop/21st Annual Conference of the EACSL},
  pages =	{426--439},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-42-2},
  ISSN =	{1868-8969},
  year =	{2012},
  volume =	{16},
  editor =	{C\'{e}gielski, Patrick and Durand, Arnaud},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2012.426},
  URN =		{urn:nbn:de:0030-drops-36888},
  doi =		{10.4230/LIPIcs.CSL.2012.426},
  annote =	{Keywords: first-order logic, regular language, automata theory, semigroup, ranker}
}
Document
Front Matter
Abstracts Collection -- 25th International Symposium on Theoretical Aspects of Computer Science

Authors: Susanne Albers and Pascal Weil

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
The Symposium on Theoretical Aspects of Computer Science (STACS) is held alternately in France and in Germany. The conference of February 21-23, 2008, held in Bordeaux, is the 25th in this series. Previous meetings took place in Paris (1984), Saarbr\"{u}cken (1985), Orsay (1986), Passau (1987), Bordeaux (1988), Paderborn (1989), Rouen (1990), Hamburg (1991), Cachan (1992), W\"{u}rzburg 1993), Caen (1994), M\"{u}nchen (1995), Grenoble (1996), L\"{u}beck (1997), Paris (1998), Trier (1999), Lille (2000), Dresden (2001), Antibes (2002), Berlin (2003), Montpellier (2004), Stuttgart (2005), Marseille (2006) and Aachen (2007).

Cite as

25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. i-xxviii, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{albers_et_al:LIPIcs.STACS.2008.1378,
  author =	{Albers, Susanne and Weil, Pascal},
  title =	{{Abstracts Collection -- 25th International Symposium on Theoretical Aspects of Computer Science}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{i--xxviii},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1378},
  URN =		{urn:nbn:de:0030-drops-13780},
  doi =		{10.4230/LIPIcs.STACS.2008.1378},
  annote =	{Keywords: Symposium, theoretical computer science, algorithms and data structures, automata and formal languages, computational and structural complexity, logic in computer science, applications}
}
Document
Preface -- 25th International Symposium on Theoretical Aspects of Computer Science

Authors: Susanne Albers and Pascal Weil

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
The interest in STACS has remained at a high level over the past years. The STACS 2008 call for papers led to approximately 200 submissions from 38 countries. Each was assigned to at least three program committee members. The program committee held a 2-week long electronic meeting at the end of November, to select 54 papers. As co-chairs of this committee, we would like to sincerely thank its members and the many external referees for the valuable work they put into the reviewing process. The overall very high quality of the papers that were submitted to the conference made this selection a difficult task. We would like to express our thanks to the three invited speakers, Maxime Crochemore, Thomas Schwentick and Mihalis Yannakakis, for their contributions to the proceedings. Special thanks are due to A. Voronkov for his EasyChair software (www.easychair.org) which gives the organisers of conferences such as STACS a remarkable level of comfort; to Ralf Klasing for helping us explore the many possibilities of this brilliant software; to Emilka Bojanczyk for the design of the STACS poster, proceedings and logo; and to the members of the Organizing Committee, chaired by David Janin. An innovation in this year's STACS is the electronic format of the publication. A printed version was also available at the conference, with ISBN 978-3-939897-06-4. The electronic proceedings are available through several portals, and in particular through HAL and DROPS. HAL is an electronic repository managed by several French research agencies, and DROPS is the Dagstuhl Research Online Publication Server. We want to thank both these servers for hosting the proceedings of STACS and guaranteeing them perennial availability. The rights on the articles in the proceedings are kept with the authors and the papers are available freely, under a Creative Commons license (see www.stacs-conf.org/faq.html for more details).

Cite as

Susanne Albers and Pascal Weil. Preface -- 25th International Symposium on Theoretical Aspects of Computer Science. In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 1-10, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{albers_et_al:LIPIcs.STACS.2008.1326,
  author =	{Albers, Susanne and Weil, Pascal},
  title =	{{Preface -- 25th International Symposium on Theoretical Aspects of Computer Science}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{1--10},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1326},
  URN =		{urn:nbn:de:0030-drops-13263},
  doi =		{10.4230/LIPIcs.STACS.2008.1326},
  annote =	{Keywords: Symposium, theoretical computer science, algorithms and data structures, automata and formal languages, computational and structural complexity, logic in computer science, applications}
}
Document
Understanding Maximal Repetitions in Strings

Authors: Maxime Crochemore and Lucian Ilie

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
The cornerstone of any algorithm computing all repetitions in a string of length $n$ in ${mathcal O(n)$ time is the fact that the number of runs (or maximal repetitions) is ${mathcal O(n)$. We give a simple proof of this result. As a consequence of our approach, the stronger result concerning the linearity of the sum of exponents of all runs follows easily.

Cite as

Maxime Crochemore and Lucian Ilie. Understanding Maximal Repetitions in Strings. In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 11-16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{crochemore_et_al:LIPIcs.STACS.2008.1344,
  author =	{Crochemore, Maxime and Ilie, Lucian},
  title =	{{Understanding Maximal Repetitions in Strings}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{11--16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1344},
  URN =		{urn:nbn:de:0030-drops-13442},
  doi =		{10.4230/LIPIcs.STACS.2008.1344},
  annote =	{Keywords: Combinatorics on words, repetitions in strings, runs, maximal repetitions, maximal periodicities, sum of exponents}
}
Document
Abstract
A Little Bit Infinite? On Adding Data to Finitely Labelled Structures (Abstract)

Authors: Thomas Schwentick

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
Finite or infinite strings or trees with labels from a finite alphabet play an important role in computer science. They can be used to model many interesting objects including system runs in Automated Verification and XML documents in Database Theory. They allow the application of formal tools like logical formulas to specify properties and automata for their implementation. In this framework, many reasoning tasks that are undecidable for general computational models can be solved algorithmically, sometimes even efficiently. Nevertheless, the use of finitely labelled structures usually requires an early abstraction from the real data. For example, theoretical research on XML processing very often con- centrates on the document structure (including labels) but ignores attribute or text values. While this abstraction has led to many interesting results, some aspects like key or other integrity constraints can not be adequately handled. In Automated Verification of software systems or communication protocols, infinite domains occur even more naturally, e.g., induced by program data, recursion, time, com- munication or by unbounded numbers of concurrent processes. Usually one approximates infinite domains by finite ones in a very early abstraction step. An alternative approach that has been investigated in recent years is to extend strings and trees by (a limited amount of) data and to use logical languages with a restricted ex- pressive power concerning this data. As an example, in the most simple setting, formulas can only test equality of data values. The driving goal is to identify logical languages and corresponding automata models which are strong enough to describe interesting proper- ties of data-enhanced structures while keeping decidability or even feasibility of automatic reasoning. The talk gives a basic introduction into data-enhanced finitely labelled structures, presents examples of their use, and highlights recent decidability and complexity results.

Cite as

Thomas Schwentick. A Little Bit Infinite? On Adding Data to Finitely Labelled Structures (Abstract). In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 17-18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{schwentick:LIPIcs.STACS.2008.1325,
  author =	{Schwentick, Thomas},
  title =	{{A Little Bit Infinite?  On Adding Data to Finitely Labelled Structures}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{17--18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1325},
  URN =		{urn:nbn:de:0030-drops-13253},
  doi =		{10.4230/LIPIcs.STACS.2008.1325},
  annote =	{Keywords: }
}
Document
Pushdown Compression

Authors: Pilar Albert, Elvira Mayordomo, Philip Moser, and Sylvain Perifel

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
The pressing need for efficient compression schemes for XML documents has recently been focused on stack computation (Hariharan and Shankar 2006, League and Eng 2007), and in particular calls for a formulation of information-lossless stack or pushdown compressors that allows a formal analysis of their performance and a more ambitious use of the stack in XML compression, where so far it is mainly connected to parsing mechanisms. In this paper we introduce the model of pushdown compressor, based on pushdown transducers that compute a single injective function while keeping the widest generality regarding stack computation. The celebrated Lempel-Ziv algorithm LZ78 was introduced as a general purpose compression algorithm that outperforms finite-state compressors on all sequences. We compare the performance of the Lempel-Ziv algorithm with that of the pushdown compressors, or compression algorithms that can be implemented with a pushdown transducer. This comparison is made without any a priori assumption on the data's source and considering the asymptotic compression ratio for infinite sequences. We prove that Lempel-Ziv is incomparable with pushdown compressors.

Cite as

Pilar Albert, Elvira Mayordomo, Philip Moser, and Sylvain Perifel. Pushdown Compression. In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 39-48, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{albert_et_al:LIPIcs.STACS.2008.1332,
  author =	{Albert, Pilar and Mayordomo, Elvira and Moser, Philip and Perifel, Sylvain},
  title =	{{Pushdown Compression}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{39--48},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1332},
  URN =		{urn:nbn:de:0030-drops-13327},
  doi =		{10.4230/LIPIcs.STACS.2008.1332},
  annote =	{Keywords: Finite-state compression, Lempel-Ziv algorithm, pumping-lemma, pushdown compression, XML document}
}
Document
Quantum search with variable times

Authors: Andris Ambainis

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
Since Grover's seminal work, quantum search has been studied in great detail. In the usual search problem, we have a collection of $n$ items $x_1, ldots, x_n$ and we would like to find $i: x_i=1$. We consider a new variant of this problem in which evaluating $x_i$ for different $i$ may take a different number of time steps. Let $t_i$ be the number of time steps required to evaluate $x_i$. If the numbers $t_i$ are known in advance, we give an algorithm that solves the problem in $O(sqrt{t_1^2+t_2^2+ldots+t_n^2)$ steps. This is optimal, as we also show a matching lower bound. The case, when $t_i$ are not known in advance, can be solved with a polylogarithmic overhead. We also give an application of our new search algorithm to computing read-once functions.

Cite as

Andris Ambainis. Quantum search with variable times. In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 49-60, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{ambainis:LIPIcs.STACS.2008.1333,
  author =	{Ambainis, Andris},
  title =	{{Quantum search with variable times}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{49--60},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1333},
  URN =		{urn:nbn:de:0030-drops-13333},
  doi =		{10.4230/LIPIcs.STACS.2008.1333},
  annote =	{Keywords: }
}
Document
Structural aspects of tilings

Authors: Alexis Ballier, Bruno Durand, and Emmanuel Jeandal

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
In this paper, we study the structure of the set of tilings produced by any given tile-set. For better understanding this structure, we address the set of finite patterns that each tiling contains. This set of patterns can be analyzed in two different contexts: the first one is combinatorial and the other topological. These two approaches have independent merits and, once combined, provide somehow surprising results. The particular case where the set of produced tilings is countable is deeply investigated while we prove that the uncountable case may have a completely different structure. We introduce a pattern preorder and also make use of Cantor-Bendixson rank. Our first main result is that a tile-set that produces only periodic tilings produces only a finite number of them. Our second main result exhibits a tiling with exactly one vector of periodicity in the countable case.

Cite as

Alexis Ballier, Bruno Durand, and Emmanuel Jeandal. Structural aspects of tilings. In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 61-72, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{ballier_et_al:LIPIcs.STACS.2008.1334,
  author =	{Ballier, Alexis and Durand, Bruno and Jeandal, Emmanuel},
  title =	{{Structural aspects of tilings}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{61--72},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1334},
  URN =		{urn:nbn:de:0030-drops-13343},
  doi =		{10.4230/LIPIcs.STACS.2008.1334},
  annote =	{Keywords: Tiling, domino, patterns, tiling preorder, tiling structure}
}
Document
Limit complexities revisited

Authors: Laurent Bienvenu, Andrej Muchnik, Alexander Shen, and Nikolay Veraschagin

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
The main goal of this paper is to put some known results in a common perspective and to simplify their proofs. We start with a simple proof of a result from (Vereshchagin, 2002) saying that $limsup_{nKS(x|n)$ (here $KS(x|n)$ is conditional (plain) Kolmogorov complexity of $x$ when $n$ is known) equals $KS^{mathbf{0'(x)$, the plain Kolmogorov complexity with $mathbf{0'$-oracle. Then we use the same argument to prove similar results for prefix complexity (and also improve results of (Muchnik, 1987) about limit frequencies), a priori probability on binary tree and measure of effectively open sets. As a by-product, we get a criterion of $mathbf{0'$ Martin-L"of randomness (called also $2$-randomness) proved in (Miller, 2004): a sequence $omega$ is $2$-random if and only if there exists $c$ such that any prefix $x$ of $omega$ is a prefix of some string $y$ such that $KS(y)ge |y|-c$. (In the 1960ies this property was suggested in (Kolmogorov, 1968) as one of possible randomness definitions; its equivalence to $2$-randomness was shown in (Miller, 2004) while proving another $2$-randomness criterion (see also (Nies et al. 2005)): $omega$ is $2$-random if and only if $KS(x)ge |x|-c$ for some $c$ and infinitely many prefixes $x$ of $omega$. Finally, we show that the low-basis theorem can be used to get alternative proofs for these results and to improve the result about effectively open sets; this stronger version implies the $2$-randomness criterion mentioned in the previous sentence.

Cite as

Laurent Bienvenu, Andrej Muchnik, Alexander Shen, and Nikolay Veraschagin. Limit complexities revisited. In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 73-84, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{bienvenu_et_al:LIPIcs.STACS.2008.1335,
  author =	{Bienvenu, Laurent and Muchnik, Andrej and Shen, Alexander and Veraschagin, Nikolay},
  title =	{{Limit complexities revisited}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{73--84},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1335},
  URN =		{urn:nbn:de:0030-drops-13350},
  doi =		{10.4230/LIPIcs.STACS.2008.1335},
  annote =	{Keywords: Kolmogorov complexity, limit complexities, limit frequencies, 2-randomness, low basis}
}
Document
Trimmed Moebius Inversion and Graphs of Bounded Degree

Authors: Andreas Björklund, Thore Husfeldt, Petteri Kaski, and Mikko Koivisto

Published in: LIPIcs, Volume 1, 25th International Symposium on Theoretical Aspects of Computer Science (2008)


Abstract
We study ways to expedite Yates's algorithm for computing the zeta and Moebius transforms of a function defined on the subset lattice. We develop a trimmed variant of Moebius inversion that proceeds point by point, finishing the calculation at a subset before considering its supersets. For an $n$-element universe $U$ and a family $scr F$ of its subsets, trimmed Moebius inversion allows us to compute the number of packings, coverings, and partitions of $U$ with $k$ sets from $scr F$ in time within a polynomial factor (in $n$) of the number of supersets of the members of $scr F$. Relying on an intersection theorem of Chung et al. (1986) to bound the sizes of set families, we apply these ideas to well-studied combinatorial optimisation problems on graphs of maximum degree $Delta$. In particular, we show how to compute the Domatic Number in time within a polynomial factor of $(2^{Delta+1-2)^{n/(Delta+1)$ and the Chromatic Number in time within a polynomial factor of $(2^{Delta+1-Delta-1)^{n/(Delta+1)$. For any constant $Delta$, these bounds are $O bigl((2-epsilon)^n bigr)$ for $epsilon>0$ independent of the number of vertices $n$.

Cite as

Andreas Björklund, Thore Husfeldt, Petteri Kaski, and Mikko Koivisto. Trimmed Moebius Inversion and Graphs of Bounded Degree. In 25th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 1, pp. 85-96, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


Copy BibTex To Clipboard

@InProceedings{bjorklund_et_al:LIPIcs.STACS.2008.1336,
  author =	{Bj\"{o}rklund, Andreas and Husfeldt, Thore and Kaski, Petteri and Koivisto, Mikko},
  title =	{{Trimmed Moebius Inversion and Graphs of Bounded Degree}},
  booktitle =	{25th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{85--96},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-06-4},
  ISSN =	{1868-8969},
  year =	{2008},
  volume =	{1},
  editor =	{Albers, Susanne and Weil, Pascal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2008.1336},
  URN =		{urn:nbn:de:0030-drops-13369},
  doi =		{10.4230/LIPIcs.STACS.2008.1336},
  annote =	{Keywords: }
}
  • Refine by Author
  • 7 Weil, Pascal
  • 3 Albers, Susanne
  • 2 Adsul, Bharat
  • 2 Crochemore, Maxime
  • 2 Erlebach, Thomas
  • Show More...

  • Refine by Classification
  • 2 Theory of computation → Algebraic language theory
  • 1 Theory of computation → Concurrency
  • 1 Theory of computation → Distributed computing models
  • 1 Theory of computation → Logic
  • 1 Theory of computation → Modal and temporal logics
  • Show More...

  • Refine by Keyword
  • 2 Combinatorics on words
  • 2 Computational Complexity
  • 2 Computational Geometry
  • 2 Mazurkiewicz traces
  • 2 Symposium
  • Show More...

  • Refine by Type
  • 64 document
  • 1 volume

  • Refine by Publication Year
  • 60 2008
  • 1 2012
  • 1 2013
  • 1 2019
  • 1 2020
  • Show More...

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