Operator Theory: Advances and Applications Vol.124 Editor: I. Gohberg Editorial Office: School of Mathematical H.G. Kaper (Argonne) Sciences ST. Kuroda (Tokyo) Tel Aviv University P. Lancaster (Calgary) Ramat Aviv, Israel L.E. Lerer (Haifa) E. Meister (Darmstadt) Editorial Board: B. Mityagin (Columbus) J. Arazy (Haifa) V. V. Peller (Manhattan, Kansas) A. Atzmon (Tel Aviv) J. D. Pincus (Stony Brook) J. A. Ball (Blacksburg) M. Rosenblum (Charlottesville) A. Ben-Artzi (Tel Aviv) J. Rovnyak (Charlottesville) H. Bercovici (Bloomington) D. E. Sarason (Berkeley) A. Böttcher (Chemnitz) H. Upmeier (Marburg) K. Clancey (Athens, USA) S. M. Verduyn-Lunel (Amsterdam) L. A. Coburn (Buffalo) D. Voiculescu (Berkeley) K. R. Davidson (Waterloo, Ontario) H. Widom (Santa Cruz) R. G. Douglas (Stony Brook) D. Xia (Nashville) H. Dym (Rehovot) D. Yafaev (Rennes) A. Dynin (Columbus) P. A. Fillmore (Halifax) Honorary and Advisory P. A. Fuhrmann (Beer Sheva) Editorial Board: S. Goldberg (College Park) C. Foias (Bloomington) B. Gramsch (Mainz) P. R. Haimos (Santa Clara) G. Heinig (Chemnitz) T. Kailath (Stanford) J. A. Helton (La Jolla) P. D. Lax (New York) M.A. Kaashoek (Amsterdam) M. S. Livsic (Beer Sheva) Recent Advances in Operator Theory The Israel Gohberg Anniversary Volume International Workshop in Groningen, June 1998 A. Dijksma MA Kaashoek A.C.M. Ran Editors Springer Basel AG Editors: A. Dijksma M.A. Kaashoek Department of Mathematics Division of Mathematics and Computer Science University of Groningen Faculty of Sciences P.O. Box 800 Vrije Universiteit 9700 AV Groningen De Boelelaan 1081a The Netherlands 1081 HV Amsterdam e-mail: [email protected] The Netherlands e-mail: [email protected] A.C.M. Ran Division of Mathematics and Computer Science Faculty of Sciences Vrije Universiteit De Boelelaan 1081a 1081 HV Amsterdam The Netherlands e-mail: [email protected] 2000 Mathematics Subject Classification 47-06; 46, 45, 30, 34, 35, 93 A CIP catalogue record for this book is available from the Library of Congress, Washington D.C., USA Deutsche Bibliothek Cataloging-in-Publication Data Recent advances in operator theory : the Israel Gohberg anniversary volume ; international workshop in Groningen, June 1998 / A. Dijksma ... ed.. - Basel; Boston ; Berlin: Birkhäuser, 2001 (Operator theory ; Vol. 124) ISBN 978-3-0348-9516-3 ISBN 978-3-0348-8323-8 (eBook) DOI 10.1007/978-3-0348-8323-8 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 other ways, and storage in data banks. For any kind of use permission of the copyright owner must be obtained. © 2001 Springer Basel AG Originally published by Birkhäuser Verlag, Basel - Boston - Berlin in 2001 Softcover reprint of the hardcover 1st edition 2001 Printed on acid-free paper produced from chlorine-free pulp. TCF <*> Cover design: Heinz Hiltbrunner, Basel ISBN 978-3-0348-9516-3 98765432 1 www.birkhasuer-science.com Israel Gohberg Contents Picture of Israel Gohberg ............................................... v Editorial preface ...................................................... xi Speeches given at the conference dinner in celebration ofIsrael Gohberg's 70-th anniversary .................................. xiii Curriculum vitae ofIsrael Gohberg ................................... xxiii Rien Kaashoek A review of the mathematical work of Israel Gohberg xxvii List of publications of Israel Gohberg ................................ xxxiii Vadim Adamyan, Reinhard Mennicken and Vjacheslav Pivovarchik On the spectral theory of degenerate quadratic operator pencils . . . . . . . .. 1 Daniel Alpay, Vladimir Bolotnikov and Leiba Rodman Two-sided tangential interpolation for Hilbert-Schmidt operator functions on polydisks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 21 D. Alpay, A. Dijksma and Y. Peretz Nonstationary analogs of the Hergiotz representation theorem: realizations centered at an arbitrary point ............................ 63 Yury Arlinskii Characteristic functions of maximal sectorial operators . . . . . . . . . . . . . . .. 89 T.Ya. Azizov, A.I. Barsukov, A. Dijksma and P. Jonas Similarity between Krein space bicontractions and Hilbert space contractions ...................................... 109 Hari Bercovici and Thomas Smotzer Classification of cyclic invariant subspaces of Jordan operators ....... 131 Paul Binding and Rostyslav Hryniv Elliptic spectral problems of higher order with eigenparameter dependent boundary conditions..................................... 145 viii Contents V.B. Bogevolnov, A.B. Mikhallova, B.S. Pavlov and A.M. Yafyasov About scattering on the ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 155 Ramon Bruzual and Marisela Dominguez Dilation of generalized Toeplitz kernels on lexicographic r x R ....... 175 HarryDym On Riccati equations and reproducing kernel spaces .. . . . . . . . . . . . . . . .. 189 Torsten Ehrhardt A status report on the asymptotic behavior of Toeplitz determinants with Fisher-Hartwig singularities ...................... 217 Volker Hardt and Reinhard Mennicken On the spectrum of unbounded off-diagonal 2 x 2 operator matrices in Banach spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 243 J. Janas and S. Naboko Multithreshold spectral phase transitions for a class of Jacobi matrices .................................................. 267 M.A. Kaashoek and H.J. Woerdeman Positive extensions and diagonally connected patterns ................ 287 Eizaburo Kamei Parametrized Furuta inequality and its applications .................. 307 I. Karelin L. Lerer and A.C.M. Ran J -symmetric factorizations and algebraic Riccati equations. . . . . . . . . .. 319 A.G. Kostyuchenko and A.A. Shkalikov Scattering of waves by periodic gratings and factorization problems .. 361 Heinz Langer, Alexander Markus and Christiane Tretter Comer of numerical ranges ......................................... 385 M.M. Malamud On some classes of extensions of sectorial operators and dual pairs of contractions ....................................... 401 S.A.M. Marcantognini and M.D. Moran Liftings of intertwining operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 451 Alexander Markus and Vladimir Matsaev Some estimates for the resolvent and for the lengths of Jordan chains of an analytic operator function . . . . . . . . . . . . . . . . . . . .. 473 Contents IX David Ogle, Nicholas Young The Parrott problem for singular values 481 B. de Pagter, F.A. Sukochev and H. Witvliet Unconditional decompositions and Schur-type multipliers ............ 505 Vyacheslav Pivovarchik Scattering in a loop-shaped waveguide ............................... 527 Steffen Roch Pseudospectra of operator polynomials .............................. 545 Editorial Preface This volume contains a selection of papers in modern operator theory and its applications. Most of them are directly related to lectures presented at the Inter national Workshop on Operator Theory and its Applications held at the University of Groningen (IWOTA-98) in Groningen, the Netherlands, from June 30-July 3, 1998. The workshop was attended by 97 mathematicians-of which 12 were PhD or postdoctoral students-from 19 countries. The program consisted of 19 plenary lectures of 40 minutes and 72 lectures of 30 minutes in 4 parallell sessions. The present volume reflects the wide range and rich variety of topics presented and discussed at the workshop. The papers deal with operator polynomials and analytic operator functions, with spectral problems of (partial) differential oper ators and related operator matrices, with interpolation, completion and extension problems, with commutant lifting and dilation, with Ricatti equations and real ization problems, with scattering theory, with problems from harmonic analysis, and with topics in the theory of reproducing kernel spaces and of spaces with an indefinite metric. All papers underwent the usual refereeing process. This volume is dedicated to Israel Gohberg, one of the initiators of the series of IWOTA workshops and president for life of its steering committee, on the occasion of his 70-th birthday. The workshop at Groningen, which is the tenth in the series, turned out to be a particularly appropriate occasion for a pre-celebration. The texts of the speeches delivered at the workshop diner, honoring Israel Gohberg and reflecting on his outstanding achievements and wonderful personality, are included in this volume. We have also added to this volume his CV and complete list of publications (listing 21 books and 401 articles), and a short description of his mathematical work. The Editors. Speeches Given at the Conference Dinner in Celebration of Israel Gohberg's 70-th Birthday At the conference dinner a number of speeches were given, as a pre-celebration ofIsrael Gohberg's 70-th birthday later that year. The texts here below have been prepared by Harm Bart, Harry Dym, Bill Helton, Heinz Langer, Alek Markus, Cora Sadosky, and Hugo Woerdeman. The order of the texts corresponds to the way the speeches were presented at the dinner. 1 To You, Izea!, by Alek Markus I have known Israel Gohberg most of my life - since 1951. And for most of my life I have been proud of being his first disciple. I don't mean the best, but the first I was. In 1959 we began to work together, for almost 15 years he was my boss and a very good boss, I have to say. Unfortunately I was not a very good subordinate, as I understand now. Whenever he asked me to do something, I immediately asked him if it was worth doing at all. He never lost patience with me and very soon I realized that he was almost always right and I was nearly always wrong. He realized that too, because he always told me: "You should never argue with me, because I am old and wise." He did seem old to me then - he was already 31 in 1959. But about 10 years before the time described, Israel was not quite so old and, I suspect, not quite so wise. To illustrate the last point I would like to tell you a story. There were two char acters in the story - one Israel Gohberg, the name of the other one will come up later. The events in the story are connected with elections to the Soviet Parlia ment. Those who lived in the former Soviet Union know that the Soviet Parliament was nothing like a parliament and the elections were nothing like elec tions. There was always one candidate for every vacant position and the result of the election was always 99.99% "for". On the morning of some election day Israel came to his polling station and took a ballot paper with the name of the only candidate ... Joseph Stalin! In accor dance with his previous firm decision Israel went into the booth, which itself was a very unusual and risky action, and crossed out the hated name. He then carefully folded the ballot paper and put the paper into the ballot box. Next morning he opened the newspaper. He was eager to know how many people were as brave as him. What he read was: ''The result of the voting for Joseph Vissarionovich Stalin
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