Jack van Lint (1932-2004) by N. G. de Bruijn Department of Mathematics and Computer Science Technological University Eindhoven email n.g.d.bruijn@tue.nl Jack van Lint died on 28 September 2004 at the age of 72. A giant in many respects, great as a mathematician, as a teacher, as a leader, as sportsman and family man, great as a helpful friend for the many people who liked him and respected him. He was full professor in mathematics at the Eindhoven University of Technology from June 1959 (at the age of 26) until his retirement in 1997. Jack started in number theory, but later he was much better known by his work in the field of discrete mathematics and its applications. He explored that area with all his energy, supported by his strong memory and his love for clarity, elegance and precision. He was great in explaining mathematics, as a speaker and as writer of articles and books. It gave him substantial influence on the many people who learned from him. Jacobus Hendricus van Lint was born on 1 September 1932 at Bandung (on the island of Java, the central island of the Dutch East Indies, now Indonesia) where his father Jacobus Hendrikus van Lint was a mathematics teacher at a secondary school. In several respects Jack became a copy of his father, who had been trained in mathematics and physics at Utrecht university and had been a passionate football player. That father was an excellent teacher, became senior master of the school, and he taught the mathematics courses at Bandung’s Technical University during Professor Boomstra’s sabbatical year. Jack once told about his father’s unbelievable memory. As director of a big school he had, right at the beginning of the year, the full timetable and the names of all the students stored in his brain. It happened that a boy knocked at his door, mentioned his name, and got to hear: ‘You are from class 2A, and you should be learning French from Mr. Blokkers right now. Anything wrong?’. Jack inherited that memory from his father. Jack’s life as a youngster was quite an adventure. Things were changing all the time, and his school education was chaotic. When Jack was 5 years old the family spent a year in Holland. After that, not back to Bandung but to Djakarta (called Batavia at that time). A few years later Jack’s father was drawn into the army as a sergeant and participated in fierce fighting at Tandjung Priok (the harbor of Djakarta) against the Japanese invaders in 1942. He survived, and got a job in the training of war pilots. A few days after the complete surrender to the Japanese these air force units were shipped to Australia. Jack’s mother managed to follow him with Jack and his younger brother Hans. In spite of air attacks they 1 boarded one of the ten civilian vessels that escaped from Tjilatjap to Australia. Seven of those were torpedoed. A few months later a longer voyage: the whole Van Lint family was shipped to the U.S., where that Dutch pilot training group was stationed at Jackson (Mississippi). Jack went to an American school, showing to be gifted in picking up a new language. Quite soon he turned out to be the best one of the class in the subject ‘English’ ! At the end of the school year Jack’s father was transferred to Chicago, where the family came into a neighborhood with many German Jewish refugees. Jack got extensively involved in social school life but nevertheless turned out to be the best one of the class. The war ended a few years later and Jack’s father had to return to what were still the Dutch East Indies. He had meanwhile specialized as a meteorologist and the army needed him for that purpose. His wife and children stayed a year in Australia, where Jack was subject to an entirely different, typically British, educational system. For him it was a lost year. They lived in Queensland at a tiny seaside village called Bargara, with no more than twenty houses. It is a very peculiar coincidence that Peter Cameron, who would coauthor several books with Jack later, had once spent some time in that village too! At the end of the year the situation in the Dutch East Indies had become very unsafe for the Dutch. Jack’s father could not stay there any longer. He left the army and the whole family made the long boat trip to the Netherlands. In the autumn of 1946 they could live with relatives at Arnhem, a city that was still heavily damaged since the battle of Arnhem two years earlier. Here Jack got, as a boy of 14, secondary school education for the first time. He had lost a year or two, but by working very hard he managed to draw level with his age group. Two years later Jack’s father got a position of school director at Zwolle, so once again Jack had to change school (and to change friends) in the middle of the school year. In 1950 he passed the final secondary school examination there. In spite of his chaotic school education in four different continents he turned out to be not just the best one of the school but the best one in the country. Nevertheless he had never been a real bookworm. He had participated in social school life, in particular in sports, even in national contests. Moreover he was very active as a boy scout, getting all existing regalia. Later in life he kept the habit of camping, always in some heavy old-fashioned boy scout tent, making totem poles and carving long wooden chains out of a trunk. For a long time he was an active football player until he damaged his Achilles’ tendon at the time he was already a professor. But as a swimmer he went on to the last year of his life, every day, early in the morning. He tried to get better and better, always using a chronometer, carefully recording distances. Once he told that thus far he had covered the distance from Eindhoven to Moscow! For his higher education Jack wanted to study mathematics, just like his father. He went to Utrecht University where he was stimulated in particular by Freudenthal, Popken and Van der Blij. He was socially active in his fraternity, even though he had made it quite difficult by promising to his father that he would not use any alcohol until passing his ‘kandidaatsexamen’ (roughly the equivalent of a bachelor degree). Needless to say he was very successful as a mathematics student. At the time the normal 2 thing was to go on to the ’doctoraal examen’ (the equivalent of a master’s degree), using at least 6 years in total. Jack did it in four and a half, graduating with distinction (January 1955). Meanwhile he had been Freudenthal’s assistent since 1952 and kept that position until September 1956. From September 1956 to June 1959 he had a grant from the Dutch Organization of Scientific Research. That enabled him to work in Germany, mainly in number theory. He spent half a year at the famous G¨ottingen university where he attended the lectures of the great Carl Ludwig Siegel, and half a year at M¨unster, working under Hans Petersson. On October 28, 1957 he got his doctorate at Utrecht University (needless to say, again with distinction). His supervisor was F. van der Blij and the subject was from the theory of modular functions ([1]). Eindhoven It was the quality of Jack’s work in number theory that the very young, but rapidly growing, Technological University at Eindhoven dared to appoint him, at the age of 26, to a full professorship in mathematics in June 1959. He accepted and always remained loyal to that institution, in spite of several other attractive proposals, both in the Netherlands and abroad. He took his duties in mathematical education and research very seriously. Furthermore his love for sports made him work hard for the promotion of sport facilities for students, like the university swimming pool. Quite rightly there still exist the yearly Van Lint Sports Week and the International Professor van Lint Tournament. He also turned to be good at university management jobs. From 1989 to 1991 he was dean of the Faculty of Mathematics and Computer Science and from 1991 to 1996 Rector Magnificus of the university. Even as professor emeritus he served two years as director of the Stan Ackermans Institute (a center for technological design). His work for getting the research school EIDMA in Eindhoven should be mentioned too. There have been 38 students who wrote their master’s thesis under Jack van Lint’s guidance. Moreover he supervised the PhD theses of H. C. A. van Tilborg (1976), H. F. H. Reuvers (1977), M. R. Best (1982), H. A. Wilbrink (1983), C. L. M. van Pul (1987), W. J. van Gils (1988), H. J. Tiersma (1989). G. J. M. van Wee (1991), Szen Ba Zhong (1992), Fang Gang (1993), I. M. Duursma (1993), P. Bours (1994), R. Struik (1994), L. M. G. M. Tolhuizen (1996), H. D. L. Hollmann (1996). Discrete mathematics Around 1965 Jack changed his mathematical subject. Jaap Seidel, the architect of the mathematics department, was aware of the fact that a school in number theory would not fit very well in a mathematics department of a technological institution. He suggested that Jack should specialize in combinatorics, the theory of structures on finite sets. That subject is called ‘discrete mathematics’ today, opposite to all mathematics dealing with continuity. Even though some of the greatest mathematicians in the past had contributed to combinatorics the subject had been, until the beginning of the twentieth century, mainly a matter of puzzles and games. In libraries it could be found under 3 headings like Unterhaltungsmathematik, math´ematiques amusantes. But during and after World War II it got important applications in many areas, like economy, logistics, biology, telecommunication, industry, to mention a few. A curriculum as the one for ‘mathematical engineer’ like one wanted to start in Eindhoven should not neglect discrete mathematics. Later in the century the triumphal march of computers would make it even much more important and central than Seidel could have foreseen in the sixties. Jack accepted the challenge. Really, it was exactly his cup of tea. He had never been impressed too much by very general theories like those of the Bourbaki revolution. He had always preferred concrete problems with simple questions and clever solutions. In order to get an adequate start he spent half a year (January to August 1966) in the famous Bell Laboratories, Murray Hill, New Jersey. He would return several times (April to August 1977, May to September 1977). Jack’s first important seminal activity was the Eindhoven Combinatorial Seminar in the years 1971-1972 and 1972-1973, adequately reported in [2]. At the Mathematical Center Amsterdam (now called CWI) he became the father of a group Discrete Mathematics that produced a full generation of talented colleagues like A. E. Brouwer, P. van Emde Boas, Jonathan Hall, H. W. Lenstra, A. Schrijver and H.C.A. van Tilborg. A few days before he died he was asked whether he had ever regretted leaving analytic number theory for discrete mathematics. He said he never did. It had become clear to him that the world of modular functions, which had been his specialty, could no longer do without modern algebraic geometry. He had not been trained in that area and thoroughly hated Bourbakism. On the other hand he could have a strong impact on discrete mathematics since analytic number theory had taught him the cooperation of algebra, number theory and analysis, in particular asymptotics. At an early stage Jack attracted attention to his work on certain classes of perfect codes, where he could prove that there were no others than those already available ([3,4,5,6]). But his name became much better known by books that surveyed large parts of the whole area of discrete mathematics. In particular his first book on coding theory of 1971 ([7]) had quite some influence. That one was extended later by editions in 1982 (also translated in Chinese), 1992 and 1998 ([8]). The books he wrote with P. Cameron ([9,10,11]) should be mentioned too here, as well as the ’Course in Combinatorics’ with R. M. Wilson ([12]). For the Dutch reader there was his ’Discrete Wiskunde’ with J. W. Nienhuys ([13]). Jack the speaker Jack was particularly appreciated as a speaker in seminars and conferences, not just since his many subjects were so interesting, but also by his lucidity and good taste, showing that mathematics could be beautiful and funny and useful, all at the same time. He kept a list of all occasions where he performed outside his own university. The list has about 300 items, most of them abroad, at more than 100 different places. In recent years he often talked on the mathematical aspects of the compact disk, on which he had worked as an advisor (since 1985) of Phillips Research Laboratories at Eindhoven. 4 Cosmopolitan Jack was a cosmopolitan already as a child and this never changed. In the days of his Eindhoven professorship he was often on leave abroad. The periods at the Bell Labs were mentioned before. Several times he stayed at the California Institute of Technology, Pasadena: September 1970-April 1971 (as Morgan Ward Visiting Professor), September 1982-August 1983 (as Fairchild Distinguished Scholar), September 1988-March 1989, April 2000-September 2000 (as Moore Distinguished Scholar). Nine international scientific journals had J. H. van Lint on the list of editors. And he was an active member on nine international committees: European Science Foundation (1977-1978), European Mathematical Council (1978-1990), International Council of Scientific Unions/CTS (1986-1994), International Committee on Mathematical Instruction (1986-1994), Nationaal Fonds voor Wetenschappelijk Onderzoek (Belgium) (1990-1997), Scientific Committee ECM ’2000 (1997-1999). In his later years he also got contacts in China. Characteristic for him is that he found it both decent and possible to learn some Chinese. With that knowledge he was able to address large audiences in China in their own language. An amusing incident took place when in 2004 a number of people in the Eindhoven mathematics library watched a videotape on which Jack spoke in fluent Chinese. By pure accident the real Jack van Lint suddenly entered the room. To our great surprise he at once began to deliver the same speech simultaneously with the speaker on the screen. A perfect playback show. Quite a few years after his Chinese speech he had still remembered all those Chinese syllables with the right tone in the right order! Honors Jack had no reason to complain about lack of recognition. Here is a list: Member of the Royal Netherlands Academy of Arts and Sciences 1972. Knight in the Order of the Lion of the Netherlands 1993. Honorary Professor Technical University Bukarest 1995. Doctor Honoris Causa University Bergen (Norway) 1996. Doctor Honoris Causa University Bukarest 1996. Honorary Professor Xi’an Jiaotong University (China). Neways Award (Eindhoven) 1997, Euler Medal of the Institute of Combinatorics and Applications (Canada) 1997. Doctor Honoris Causa University Gent (Belgium) 2000. Honorary Member of the Dutch Mathematical Society (Koninklijk Wiskundig Genootschap) 2004. 5 Many important mathematicians have had the honor of being invited lecturer at international mathematical congresses, but Jack had this four times: Warsaw 1983, Berkeley 1986, Kyoto 1990, Berlin (Urania Lectures) 1998. Moreover he was invited three times for a lecture at international congresses on mathematical education: Karlsruhe 1976, Berkeley 1980, Adelaide 1984. Jack van Lint as a person In spite of the unbridled energy he used as a mathematician he was a quite social and pleasant man. Always a dependable and adventurous leader of a happy family, in particular on the longer trips abroad where his wife Betty and the two children joined him. In his circle of friends he was always a good conversationalist, full of interesting stories, sometimes slightly exaggerated. In his hobbies he was enthusiastic, rigorous and faithful. In the first place was there his love for sports like swimming and football. From childhood he was an expert stamp collector. In later years he specialized in complete postal articles that were stories in themselves by everything that was stamped and written on them. And he was a fervent bridge player. For students and colleagues he used to be very helpful. And he was always available for assistance with heavy garden work for his neighborhood. In the last two years of his life Jack suffered from the after-effects of a serious operation. Nevertheless he managed to make the best of it. It was business as usual, regularly coming to his work in Eindhoven too. But in the summer of 2004 his situation turned out to be hopeless. Within a few weeks he died, in full conscience that his life had been a good one. That was the end of an outstanding and unbelievably energetic man. A younger colleague, Aart Blokhuis, summarized it by saying that so often he had had the impression that there were three Jack van Lints! Acknowledgements For help with this obituary the author is indebted to H. van Tilborg, F. van der Blij, A. Schrijver, but in the first place to Jack van Lint for all he had left. The website http://www.win.tue.nl/~jlint contains material he had collected himself: 1. Curriculum Vitae. 2. A list of his writings: scientific journal publications (about 150), books and addresses. 3. A list of seminar talks in the Netherlands and abroad. References 1. J. H. van Lint. Hecke operators and Euler products. Academisch proefschrift, Utrecht 1957. 6 2. J. H. van Lint. Combinatorial Theory Seminar Eindhoven University of Technology, Lecture Notes in Mathematics 382, Springer Verlag, 1974. 3. J. H. van Lint, On the non-existence of certain perfect codes. In: Computers and Number Theory, Academic Press, London, 277-282. 4. J. H. van Lint, On the non-existence of perfect 2- and 3-Hamming-error-correcting codes over the alphabet GF(q). Information and Control 16 (1970), 369-401. 5. J. H. van Lint, Non-existence theorems for perfect error-correcting codes. Computers in Algebra and Number Theory, SIAM-AMS Colloquia 3, 89-95. 6. J. H. van Lint, Non-existence of perfect 5-, 6- and 7-Hamming-error-correcting codes over GF(q). Report 70-WSK-06, Eindhoven University of Technology. 7. J. H. van Lint, Coding Theory, Lecture Notes in Mathematics 201, Springer Verlag, 1971. 8. J. H. van Lint, Introduction to Coding Theory. Graduate Texts in Mathematics 86, Springer Verlag 1982, second edition 1992, third (enlarged) edition 1998. 9. P. Cameron and J. H. van Lint, Graph Theory, Coding Theory and Block Designs, London Math. Soc. Lecture Notes 19, Cambridge University Press, 1975. 10. P. Cameron and J. H. van Lint, Graphs, Codes and Designs, London Math. Soc. Lecture Note Series 43, Cambridge University Press, 1980. 11. P. Cameron and J. H. van Lint, Designs, Graphs, Codes and their Links, London Math. Soc. Student Texts 22, Cambridge University Press, 1991. 12. J. H. van Lint and R. Wilson, A Course in Combinatorics, Cambridge University Press 1991. 13. J. H. van Lint en J. W. Nienhuys, Discrete Wiskunde, Academic Press, 1991. 7
Go to Kathy and Rick's visit to Holland for the Symposium in honor of Jack van Lint. Jack was the co-author of Rick's book on Combinatorics