Israel Gohberg and Friends On the Occasion of his 80th Birthday Harm Bart Thomas Hempfling Marinus A. Kaashoek Editors Birkhäuser Basel · Boston · Berlin Editors: Harm Bart Marinus A. Kaashoek Econometrisch Instituut Department of Mathematics, FEW Erasmus Universiteit Rotterdam Vrije Universiteit Postbus 1738 De Boelelaan 1081A 3000 DR Rotterdam 1081 HV Amsterdam The Netherlands The Netherlands e-mail: [email protected] e-mail: [email protected] Thomas Hempfling Editorial Department Mathematics Birkhäuser Publishing Ltd. P.O. Box 133 4010 Basel Switzerland e-mail: thomas.hempfl[email protected] Library of Congress Control Number: 2008927170 Bibliographic information published by Die Deutsche Bibliothek Die Deutsche Bibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data is available in the Internet at <http://dnb.ddb.de>. ISBN 978-3-7643-8733-4 Birkhäuser Verlag, Basel – Boston – Berlin 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. © 2008 Birkhäuser Verlag AG Basel · Boston · Berlin P.O. Box 133, CH-4010 Basel, Switzerland Part of Springer Science+Business Media Printed on acid-free paper produced of chlorine-free pulp. TCF ∞ Printed in Germany ISBN 978-3-7643-8733-4 e-ISBN 978-3-7643-8734-1 9 8 7 6 5 4 3 2 1 www.birkhauser.ch Contents Preface.......................................................................ix CongratulationsfromthePublisher...........................................xii PartI.MathematicalandPhilosophical-MathematicalTales...................1 I. Gohberg MathematicalTales ......................................................3 I. Gohberg Philosophical-MathematicalTales:A PersonalAccount .................35 Z. Faro-Gohberg and Y. Israeli-Gohberg OurDad’sMathematics ................................................41 PartII.WorkandPersonalia.................................................51 CurriculumVitaeofIsraelGohberg .....................................53 ListofPublicationsofIsraelGohberg ...................................57 ListofPh.D.StudentsofIsraelGohberg ................................97 ReferenceofM.G.Krein ................................................99 ElectionAcademyMoldova ............................................101 M.A. Kaashoek ReviewoftheMathematicalWorkofIsraelGohberg ...................105 M.A. Kaashoek and L. Lerer Gohberg’s Mathematical Work in the Period 1998–2008 . .111 TheNathanandLilySilverChair .....................................117 PartIII.GohbergMiscellania:Celebratingthe60thBirthday...............119 PartIV.Celebratingthe70thBirthday.....................................141 PartV.AboutColleaguesandFriends......................................153 I. Gohberg OpeningAddress.ToeplitzMemorialConference .......................155 I. Gohberg, M.S. Livˇsic and I. Piatetski-Shapiro David Milman (1912–1982) . 157 H. Dym, I. Gohberg and N. Kravitsky Biography of M.S. Livˇsic ..............................................163 vi Contents I. Gohberg OdessaReminiscences .................................................169 I. Gohberg Opening Address at the M.A. Kaashoek 60th Birthday Workshop in Amsterdam, November 1997 ................................ .173 I. Gohberg MarkGrigorievichKrein:Recollections ................................177 A. Dijksma and I. Gohberg HeinzLangerandhisWork ............................................189 I. Gohberg Vladimir Maz’ya: Friend and Mathematician. Recollections . 209 I. Gohberg Reminiscences of B´ela Sz˝okefalvi-Nagy.................................213 I. Gohberg PeterLancaster,myFriendandCo-author ............................ 217 I. Gohberg OnJointWorkwithHarryDym .......................................221 R.L. Ellis and I. Gohberg In Memoriam Seymour Goldberg (1928–2004) . 227 A. B¨ottcher, I. Gohberg and B. Silbermann In Memoriam Georg Heinig (1947–2005) . 231 I. Gohberg Recollections: Vasile Grigorievich Ceban, on his 90th Birthday . 235 I. Gohberg HeinzLanger,myFriedandColleague– Recollections .................239 I. Gohberg and M.A. Kaashoek OurMeetingswithErhardMeister ....................................243 PartVI.HonoraryDoctorates:LaudatiosandReplies.......................245 Darmstadt,Germany ..................................................247 Vienna,Austria .......................................................249 Timi¸soara,Rumania ...................................................255 Cisinau,Moldova ......................................................263 Balti,Moldova ........................................................269 Technion,Haifa,Israel .................................................271 Contents vii Part VII. Festschrift 2008............................... 275 D. Alpay Collaborating with Israel Gohberg: Some Personal Thoughts . 277 J.A. Ball MyCollaborationwithIsraelGohberg .................................281 H. Bart IsraelGohberg:a Teacheranda Friend ................................283 A. B¨ottcher LinearandOne-dimensional ...........................................289 H. Dym Rehovot Days Redux2 .................................................293 Y. Eidelman IsraelTsudikovich:MyOlderColleagueandOlderFriend ..............295 R.L. Ellis EightFriends ..........................................................297 A.E. Frazho IsraelGohbergandEngineering .......................................299 M.A. Kaashoek ProfessoratAmsterdam:ThankyouIsrael! ............................301 P. Lancaster IGandMe ............................................................307 H.J. Landau ToIsrael ..............................................................309 J. Leiterer Froma YoungStudenttoanOlderOne ...............................311 Ran What About Stability? ................................. ...............313 L. Rodman Israel Gohberg and his Influence on my Mathematical Life .... .........315 B. Silbermann The First Visits of Israel Gohberg to Karl-Marx-Stadt (Chemnitz) . 317 I. Spitkovsky MyGohbergEncounters ...............................................319 F. van Schagen Becominga Co-author .................................................321 Pictures.....................................................................323 Preface Mathematicians do not work in isolation. They stand in a long and time honored tradition. They write papers and (sometimes) books, they read the publications of fellow workers in the field, and they meet other mathematicians at conferences all over the world. In this way, in contact with colleagues far away and nearby, from the past (via their writings) and from the present, scientific results are obtained which are recognized as valid. And that – remarkably enough – regardless of ethnic background, political inclination or religion. In this process, some distinguished individuals play a special and striking role. They assume a position of leadership. They guide the people working with them through uncharted territory, thereby making a lasting imprint on the field. Some- thing which can only be accomplished through a combination of rare talents: un- usually broad knowledge, unfailing intuition and a certain kind of charisma that binds people together. All of this is present in Israel Gohberg, the man to whom this book is dedicated, on the occasion of his 80th birthday. This comes to the foreground unmistakably from the contributions from those who worked with him or whose life was affected by him. Gohberg’s exceptional qualities are also apparent from the articles written by himself, sometimes jointly with others, that are reproduced in this book. Among these are stories of his life, some dealing with mathematical aspects, others of a more general nature. Also included are reminiscences paying tribute to a close colleague who is not among us any more, speeches or reviews highlighting the work and personality of a friend or esteemed colleague, and responses to the laudatio’s connected with the several honorary degrees that were bestowed upon him. The documents collected here give a fascinating and sometimes moving insight in the human factors that influence the development of mathematics. The focus is not on formal mathematical results but instead on the personal relationships that con- stitute the underlying propelling-power in scientific cooperation. Centered around the remarkable figure of Israel Gohberg, a picture emerges of the development of operator theory and its applications during the last four or five decades. The book is divided in seven parts which we will now briefly describe. Part I. This part contains two presentations written by Gohberg himself in which he speaks about his mathematical development in former years and on some gen- eral, philosophically tinted aspects of mathematics. It also features a piece written xPreface by the two Gohberg daughters, Zvia and Yanina, giving an impression of what it meant to be the children of a loving father leading a life devoted to mathematics. Part II. This part starts with some documents carrying factual information: Goh- berg’s curriculum vitae, a list of his publications and a list of his Ph.D students. Also included are a translation of a letter of reference written by M.G. Krein, when Gohberg was a master student, and translations of letters and telegrams supporting his nomination as a corresponding