Lecture Notes in Computer Science 7020 Commenced Publication in 1973 Founding and Former Series Editors: Gerhard Goos, Juris Hartmanis, and Jan van Leeuwen Editorial Board David Hutchison Lancaster University, UK Takeo Kanade Carnegie Mellon University, Pittsburgh, PA, USA Josef Kittler University of Surrey, Guildford, UK Jon M. Kleinberg Cornell University, Ithaca, NY, USA Alfred Kobsa University of California, Irvine, CA, USA Friedemann Mattern ETH Zurich, Switzerland John C. Mitchell Stanford University, CA, USA Moni Naor Weizmann Institute of Science, Rehovot, Israel Oscar Nierstrasz University of Bern, Switzerland C. Pandu Rangan Indian Institute of Technology, Madras, India Bernhard Steffen TU Dortmund University, Germany Madhu Sudan Microsoft Research, Cambridge, MA, USA Demetri Terzopoulos University of California, Los Angeles, CA, USA Doug Tygar University of California, Berkeley, CA, USA Gerhard Weikum Max Planck Institute for Informatics, Saarbruecken, Germany
Werner Kuich George Rahonis (Eds.) Algebraic Foundations in Computer Science Essays Dedicated to Symeon Bozapalidis on the Occasion of His Retirement 13
Volume Editors Werner Kuich Technische Universität Wien Institut für Diskrete Mathematik und Geometrie 1040 Wien, Austria E-mail: kuich@tuwien.ac.at George Rahonis Aristotle University of Thessaloniki Department of Mathematics 54124 Thessaloniki, Greece E-mail: grahonis@math.auth.gr The illustration appearing on the cover of this book is the work of Daniel Rozenberg (DADARA). ISSN 0302-9743 e-issn 1611-3349 ISBN 978-3-642-24896-2 e-isbn 978-3-642-24897-9 DOI 10.1007/978-3-642-24897-9 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2011938838 CR Subject Classification (1998): F.4, D.3, F.3.2, I.1, F.4.1, D.2.4 LNCS Sublibrary: SL 1 Theoretical Computer Science and General Issues Springer-Verlag Berlin Heidelberg 2011 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Typesetting: Camera-ready by author, data conversion by Scientific Publishing Services, Chennai, India Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)
Symeon Bozapalidis
Preface This Festschrift is published in honor of Symeon Bozapalidis (born in Thessaloniki, Greece on April 5, 1948) on the occasion of his retirement. Symeon completed his undergraduate studies at the Department of Mathematics of the Aristotle University of Thessaloniki in 1970, his doctorate at the Department of Mathematics of the University of Ioannina in 1973, and his second doctorate, in 1976, at Université Paris 7, France. He became a full professor of algebra at the age of 32 at the University of Ioannina, and moved to the Aristotle University of Thessaloniki in 1982. His initial research was focused on algebra and especially on categories theory. In the 1980s he turned to theoretical computer science. His main interests are closely connected with algebraic foundations in computer science, which is why we chose this title for this volume. In particular, he contributed to the development of the theory of tree languages and series, the axiomatization of graphs, a deep consideration of picture theory, and fuzzy languages. He never stopped working and producing seminal results despite his serious sight problems. He was awarded twice, in 2000 and 2005, for his research by the most prestigious organization in Greece, the Academy of Athens. The contribution of Symeon to algebraic informatics is not limited to his publications. He organized the Third International Conference of Developments in Language Theory (DLT 1997), the Workshop on Current Trends and Developments in Fuzzy Logic in 1998, and he initiated the International Conference on Algebraic Informatics (CAI) series in 2005. Symeon is (because after his official retirement in 2010 his students are still being taught by him) also an excellent teacher. He taught for more than 35 years several subjects such as algebra, linear algebra, mathematical logic, number theory, and in addition, after 1982, automata theory, tree languages and series, algebraic semantics, and fuzzy languages. Seven PhD theses were completed under his supervision. This Festschrift volume contains 15 invited papers which are all connected to Symeon s research topics. They are written by colleagues, friends, and students of Symeon. All the papers were refereed according to the usual journal standards. We are deeply grateful to all the authors for their kind contribution; in fact the whole project turned out to be a nice and friendly procedure. Most of the papers were presented at the Workshop of Algebraic Foundations in Computer Science, held in Thessaloniki, during November 7 8, 2011. Last but not least we would like to express our gratitude to the team at Springer for their excellent, as usual, cooperation. August 2011 Werner Kuich George Rahonis
Workshop on Algebraic Foundations in Computer Science Organizers Werner Kuich, Vienna Dimitrios Poulakis, Thessaloniki George Rahonis, Thessaloniki Local Organizing Committee Eleni Mandrali Irini Eleftheria Mens Dimitrios Poulakis (Co-chair) George Rahonis (Chair) Eleni Maria Vretta
Table of Contents Selected Decision Problems for Square-Refinement Collage Grammars... 1 Frank Drewes Weighted Tree Automata over Valuation Monoids and Their Characterization by Weighted Logics... 30 Manfred Droste, Doreen Götze, Steffen Märcker, and Ingmar Meinecke Partial Conway and Iteration Semiring-Semimodule Pairs... 56 Zoltán Ésik Kleene Theorem in Partial Conway Theories with Applications... 72 Zoltán Ésik and Tamás Hajgató Rational Transformations and a Kleene Theorem for Power Series over Rational Monoids... 94 Ina Fichtner and Christian Mathissen Equational Weighted Tree Transformations with Discounting... 112 Zoltán Fülöp and George Rahonis Quantum Automata Theory A Review... 146 Mika Hirvensalo Graph Automata: The Algebraic Properties of Abelian Relational Graphoids... 168 Antonios Kalampakas A Survey on Picture-Walking Automata... 183 Jarkko Kari and Ville Salo Identity Problems, Solvability of Equations and Unification in Varieties of Semigroups Related to Varieties of Groups... 214 Ondřej Klíma and Libor Polák Algebraic Systems and Pushdown Automata... 228 Werner Kuich Where Automatic Structures Benefit from Weighted Automata... 257 Dietrich Kuske
X Table of Contents Survey: Weighted Extended Top-Down Tree Transducers: Part III Composition... 272 Aurélie Lagoutte and Andreas Maletti Valuations of Weighted Automata: Doing It in a Rational Way... 309 Ingmar Meinecke Selected Combinatorial Properties of Random Intersection Graphs... 347 Sotiris Nikoletseas, Christoforos Raptopoulos, and Paul G. Spirakis Author Index... 363