Rolf Nevanlinna Colloquia is today an esteemed institution in the field of complex analysis, started as a consequence of Rolf Nevanlinna's activity at the University of Zürich between 1946-1963. When Nevanlinna retired in 1963, some of his colleagues and former students, Hans Künzi and Kurt Strebel in the forefront, made an initiative to organize Nevanlinna Colloquia on a regular basis. This initiative met with a positive reaction. The official purpose of the Colloquia was to promote scientific relations between Finland and Switzerland by organizing lectures and scientific colloquia. However, as described in the article by Kurt Strebel, the initiative was also designed to bring Rolf Nevanlinna back to Zürich again, at least for short annual visits.
The unofficial purpose succeeded for some time, beginning with the first Rolf Nevanlinna Colloquium held in Zürich, on June 2-3, 1964. At this first Colloquium, Rolf Nevanlinna himself was the only speaker. On June 2, he delivered a lecture ``Über Systeme von partiellen Differentialgleichungen" at the Zürich Mathematical Colloquium. The following day he gave a lecture ``Über die Situation der Mathematik im heutigen Kulturleben" before a general audience at the Auditorium Maximum of the University of Zürich.
One may loosely divide the series of Rolf Nevanlinna Colloquia up to now (Table 1) into two subsequent periods. The first ten Colloquia may be regarded as the ``mathematical family meetings" around Nevanlinna. Of course, as sometimes in real life, the family was gradually expanding. A second characteristic of this period was to have only invited speakers at the Colloquia. The number of speakers fluctuated, from a single speaker in 1964 and 1966 up to seventeen speakers in 1975. The larger Colloquia in 1965 and 1975 celebrated the 70th and 80th birthday of Rolf Nevanlinna. A third characteristic, well remembered by the participants, were the memorable banquets held at some of the famous ``Zunfthaus"-restaurants in Zürich. In particular, the banquet at the ``Zunfthaus zur Saffran" in 1975 surely remains vivid in the minds of all those present there. On that occasion, Rolf Nevanlinna gave a speech full of personal reminiscences. The 10th Rolf Nevanlinna Colloquium had been prepared for 1980, in order to celebrate the 85th birthday of Nevanlinna. However, he died on May 28, 1980, and plans had to be changed. A Memorial Colloquium was held in Zürich in March 5-6, 1981.
At this point, the future of the Colloquia seemed to be endangered. After some discussions, mainly between Kurt Strebel and Olli Lehto, an informal decision was made to organize Nevanlinna Colloquia not only in Switzerland, but also in Finland.
The above decision started the second period of these Colloquia: seven events have been organized so far, including the centenary celebration in 1995. Only two of these seven colloquia has been held in Zürich; four have been held in Finland, and one - as an exception - in U.S.A., the first time outside of Switzerland and Finland. Except for the 12th Colloquium in Zürich, which followed the traditional pattern, the colloquia of the second period reveal a somewhat different approach, if compared with earlier Colloquia. In fact, the total number of speakers tends to be increasing. Moreover, in addition to invited plenary speakers, parallel sessions have been introduced. A record number of plenary speakers (25) was reached in Ann Arbor, while the total number of lectures was one hundred in Joensuu in 1987.
The list of plenary speakers at the Rolf Nevanlinna Colloquia up to now (Table 2) has the names of 116 distinguished mathematicians. This list represents a fairly complete coverage of the best contemporary state-of-art in function theory and some related areas. The most frequent plenary speakers have been O. Lehto, having addressed the Colloquia six times, followed by H. Wittich with five lectures. L. Ahlfors, L. Carleson, F. Gehring, W. K. Hayman and I. S. Louhivaara have each delivered four plenary lectures. One of the founders, K. Strebel, as well as A. Pfluger, H. M. Reimann and O. Martio, have spoken three times. Participation in the Nevanlinna Colloquia has been international from the very beginning, although complete information apparently disappeared already. The first period clearly reflects the original idea of the Colloquia to promote scientific relations between Finland and Switzerland. During 1964-1981, 62 of the total of 75 plenary speakers represented Switzerland (19), U.S.A. (16), Germany (14) and Finland (13). However, during the second period, the position of U.S.A. (40) became quite dominant. U.S.A., Finland and Switzerland together account for 59 of the total of 80 plenary speakers during the second period. Altogether, 17 nationalities have been represented among the plenary speakers up to the present time.
When considering the fields of mathematics represented by the main lectures between 1964-1993, four broad fields dominate: (1) Conformal, quasiconformal and quasiregular mappings, (2) partial differential equations and potential theory, (3) Riemann surfaces and differential geometry and (4) value distribution theory and complex differential equations. These four fields account for about 65 % of all plenary lectures.
Table 1
| Place | Time | (1) | (2) | (3) | |
| 1. | Zürich | 1964, June 2-3 | 1 | 2 | |
| 2. | Zürich | 1965, November 4-6 | 14 | 14 | |
| 3. | Zürich | 1966, November 29 | 1 | 1 | |
| 4. | Zürich | 1967, November 28 | 3 | 3 | |
| 5. | Zürich | 1969, June 4 | 2 | 2 | |
| 6. | Zürich | 1971, June 18-19 | 12 | 12 | |
| 7. | Zürich | 1973, November 2-3 | 9 | 9 | |
| 8. | Zürich | 1975, November 6-8 | 17 | 17 | |
| 9. | Zürich | 1977, November 11-12 | 6 | 6 | |
| 10. | Zürich | 1981, March 5-6 | 10 | 10 | |
| 11. | Jyväskylä | 1983, August 10-13 | 5 | 46 | |
| 12. | Zürich | 1985, June 13-15 | 12 | 12 | |
| 13. | Joensuu | 1987, August 10-13 | 9 | 100 | 160 |
| 14. | Helsinki | 1990, June 10-14 | 11 | 37 | 100 |
| 15. | Ann Arbor | 1993, June 3-9 | 25 | 78 | 130 |
| 16. | Joensuu | 1995, August 1-5 | 10 | 55 | 194 |
| 17. | Lausanne | 1997, August 14-20 | 12 | 45 | 109 |
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(2) Total number of speakers according to the Colloquium program.
(3) Approximate number of participants, if available.
Table 2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Ahlfors, L. x x x x
Andreian-Cazacu, C. x
Arbarello, E. x
Astala, K. x
Basmajian, A. x
Bemelmans, J. x
Bishop, C. x
Bleuler, K. x
Bombieri, E. x
Bowers, P. x
Brooks, R. x
Buser, P. x
Cannon, J. x
Carleson, L. x x x x
Catanese, F. x
Constantinescu, C. x
Douady, A. x
Drasin, D. x x
Edrei, A. x
Eremenko, A. x x
Erkama, T. x
Fehlmann, R. x
Frank, G. x
Fuchs, W. x
Fuglede, B. x
Gaier, D. x
Gehring, F. x x x x
Gordon, C. x
Griffiths, P. x
Gromov, M. x
Grunsky, H. x
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Haahti, H. x
Hassner, M. x
Hayman, W. K. x x x x
Heinonen, J. x x
Heins, M. x
Helgason, S. x
Hersch, J. x
Hess, P. x
Holmann, H. x
Hörmander, L. x
Huber, H. x
Huber, A. x x
Huckemann, F. x
Iwaniec, T. x x
Jones, P. x
Jorgensen, T. x
Kapovich, M. x
Keller, H. x
Keller, S. x
Koepf, W. x
Kotschik, D. x
Kra, I. x
Kruzhilin, N. x
Krzy\.z, J. x
Kühnau, R. x
Kuiper, N. x
Kupiainen, A. x
Lakic, N. x
Lehto, O. x x x x x x
Lelong, P. x
Leutwiler, H. x
Lewis, J. x
Lions, J. x
Lohwater, J. x
Louhivaara, I. S. x x x x
Mackey, G. x
Makarov, N. x x
Malý, J. x
Marden, A. x x
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Martio, O. x x x
McMullen, C. x
Meier, K. x
Moser, J. x
Mues, E. x
Nevanlinna, R. x x
Ohtsuka, M. x
Pfluger, A. x x x
Phong, D. x
Pinkall, U. x
Pleijel, Å. x
Polya, G. x
Pommerenke, C. x
Reich, E. x
Reimann, H. M. x x x
Rickman, S. x x
Robert, A. x
Röhrl, H. x
Royden, H. x
Rüedy, R. x
Saito, K. x
Schmutz Schaller, P. x
Schramm, O. x
Schumacher, G. x
Sela, Z. x
Semmes, S. x
Siu, Y.-T. x
Stampacchia, G. x
Steiner, A. x x
Stephenson, K. x
Storvick, D. x
Strebel, K. x x x
Struwe, M. x
Sullivan, D. x
Takhtajan, L. x
Taniguchi, M. x
Toppila, S. x
Tromba, A. x
Tukia, P. x
Volberg, A. x
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Vuorinen, M. x
Väisälä, J. x
Weitsman, J. x
Wittich, H. x x x x x
Wolpert, S. x x
Zelditch, S. x