Hoàng Tụy

Discover the latest articles, books and news in related subjects, suggested using machine learning. In 1987, we were both, A. Migdalas and P. Värbrand, preparing the final stages of our PhD Theses under the supervision of Prof. Kurt Jörnsten—who was the head of the optimization group in Linköping. A. Migdalas was working on a theme on traffic planning and network design. The network design problem either in its classical form or in its two-level form is essentially a nonconvex problem. At the same time, P. Värbrand was starting to look at linear bilevel problems and we both realized that in order to attack these problems, we would need to deepen our knowledge in nonconvex or global optimization—and we came in contact with the work of Hoàng Tuy. In 1988, A. Migdalas got a position at Århus University in Denmark, in the optimization group under the leadership of Prof. Jörgen Tind. During this stay, Jörgen Tind invited Hoàng Tuy for a short visit and that was our first meeting. We started to discuss several problems, including single- and two-level network design problems and we held contact and continued to discuss these problems even after Hoàng Tuy’s departure to Germany where he was preparing the first book on “Global Optimization” in collaboration with Reiner Horst. Since then, Hoàng Tuy has written numerous papers contributing to the advancement of the field of Global Optimization and optimization in general. He has authored and co-authored several books, including a first complete book on “Global Optimization” in 1990, as well as the books “Optimization on Low Rank Nonconvex Structures” in 1996, and “Convex Analysis and Global Optimization” in 1998. Despite his high age, Hoàng Tuy continued to work with clear spirit and delight, generating new ideas and new publications. In 2016, he revised and updated the book “Convex Analysis and Global Optimization” to include modern approaches to minimax, fixed point, and equilibrium theorems, and to nonconvex optimization and new topics on monotonic optimization, polynomial optimization and optimization under equilibrium constraints, bilevel programming, multi-objective programming, and optimization with variational inequality constraint. Hoàng Tuy spent considerable time as invited guest professor at leading universities around the world, including Linköping University, as we mentioned above. In 1995, Hoàng Tuy accepted an honorary doctor’s degree from the Technical Faculty at Linköping University at a time when Prof. Sven Erlander was spending his last term as President of Linköping University. Hoàng Tuy lived most of his early life under difficult conditions due to the Vietnam War. He was an outstanding high school teacher and even wrote a text book on geometry that was published by the Vietnamese guerrilla in 1949. In 1951, Hoàng Tuy made the long walk to north along the Ho Chi Minh trail carrying only his math books and some rice and salt. Hoàng Tuy was to large extent a self-taught mathematician. Indeed, he followed the Soviet university program in mathematics on his own! After moving to Moscow, he received the PhD degree from the Moscow University under the supervision of Prof. Vladimir Menshov and Prof. Georgiy E. Shilov in just one and half years of study. He even published five papers in real analysis in Soviet journals written in Russian, a language that he succeeded to learn by studying mathematics from Russian books. Hoàng Tuy became vice chairman of the Institute of Mathematics in Hanoi when it was established in 1970 and he served as chairman from 1980. He became General Secretary of the Vietnamese Mathematical Society the same year. We are very proud and deeply grateful for having had the privilege to work with Hoàng Tuy. His inspiration, knowledge, and encouragement during his regular visits to Linköping University in the late 1980s and early 1990s has meant a lot to us personally but also to the whole Optimization division. We have learned to know Hoàng Tuy