Professor Donald G. Aronson, who joined the faculty of the University of Minnesota in 1957, will retire this June. He received his Ph.D. from the Massachusetts Institute of Technology in 1956 under the direction of Norman Levinson, and he came to Minnesota after a year and a half as a research associate at the University of Illinois. He was promoted to Associate Professor in 1962, and to Professor in 1965. He spent the 1961-1962 academic year at Stanford University as an NSF Postdoctoral Fellow and also held numerous visiting professorships.
Don is famous for his work on the porous medium equation and on dynamical systems theory. He has also done well-known pioneering work on linear and nonlinear parabolic equations. He was an invited speaker at many prestigious conferences and gave a one-hour address at the 1987 AMS annual meeting in Salt Lake City. He is the author of 83 scientific publications. A conference in Don's honor, titled "Nonlinear Phenomena in Science," was held at the Free University of Amsterdam, June 6-8, 2001 on the occasion of his 70th birthday. At this three-day conference many distinguished speakers presented research in areas where Don has had fundamental impact. Don is a very outgoing person and enjoys collaborating with other mathematicians and scientists. Among his distinguished coauthors are James Serrin, Hans Weinberger, Rutherford Aris, Hans Othmer, Dick McGehee and John Lowengrub from Minnesota, as well as Sigurd Angenent, Luis Caffarelli, Martin Golubitsky, Nancy Kopell, Bert Peletier, Juan Vazquez and many others. Don had five Ph.D. students and seven postdoctoral students. His professed dislike of administration notwithstanding, he served for two years as Director of Graduate Studies (1969-1971), and as Associate Director of the Geometry Center in 1997-1998.
Don and his wife Claire have also played an active role in the social life of the School of Mathematics and the general community. We wish them many more happy and productive years.
Professor Charles McCarthy, who has been on our faculty since 1961, will retire this coming June. His specialty is Functional Analysis and Operator Theory. Charlie obtained his Ph.D. from Yale University in 1959 under Einar Hille. He spent the next two years at MIT as a Moore Instructor before joining the U of M faculty in 1961 as an Assistant Professor. He was promoted to Associate Professor in 1963 and to Professor in 1967. In 1963, he was awarded the prestigious Sloan Foundation Fellowship, which enabled him to spend the 1963-19 64 academic year at the Courant Institute of New York University. He held visiting professorships at the University of Sussex and Chalmers Institute of Technology. When the personal computers first made their appearance, Charlie played an important role in bringing this technological advance to the department. He served as Director of Graduate Studies during the 1999-2000 academic year, and for a number of years enthusiastically coached our Putnam Exam team. He and his wife Floren, who received her Master's degree in our department, look forward to low-key traveling. We wish them continued happiness in life.
Professor Yasutaka Sibuya retired in June 2001, after 38 years at the University. He earned his Ph.D. degree in 1959 from UCLA under Earl Coddington, and a Doctor of Sciences degree from the University of Tokyo in 1961. He joined the University of Minnesota faculty in 1963 as an Associate Professor, after holding faculty positions at MIT and the Courant Institute. He was promoted to the rank of Professor in 1965. Professor Sibuya's research is in the area of differential equations. He is the author, or co-author, of 120 scientific publications and his distinguished contributions have been highly recognized. He has had many prestigious speaking invitations, including an AMS one-hour address in 1982. He was the recipient of the Alexander von Humboldt Award for the Senior U.S. Scientists for 1985, served on the editorial boards of professional journals, and held several visiting professorships at leading research centers worldwide. He supervised eight Ph.D. students, passing on to them his high standard and enthusiasm for mathematics. A dinner in Professor Sibuya's honor, held April 10, 2001, was attended by numerous colleagues. Several of them expressed their deep appreciation for his generous sharing of time and ideas over many years. We wish him many happy and profitable years to come.