To the Memory of Jack K. Hale (1928-2009)

Yingfei Yi

In the Emory Hospital of Atlanta, in the early morning of December 9, 2009, there passed away a great man, Jack K. Hale -- a founding father of numerous areas of modern dynamics, a noble scholar and teacher, and a mentor and dear friend of many of us around the world.

Jack in his backyard in Atlanta, June 1992.

Needless to say, Jack is among the most influential and respected persons in the field, leading the exciting development of the field for the past four decades. In my 2003 interview with Jack for the SIAM DSWeb Magazine (link), one can find some traces to that part of the history and the unique role which Jack played in leading the way. His many landmark contributions to the field are now well documented in several special volumes of professional journals in his honor: the special volume of Proceedings of the Royal Society of Edinburgh (113 (1989), 118 (1991), edited by J. M. Ball) dedicated to his 60^th birthday, the special volume of Journal of Differential Equations (169, No. 1 & 2 (2001), edited by K. Mischaikow and Y. Yi) dedicated to his 70^th birthday, and the special volume of Journal of Dynamics and Differential Equations (22 No. 1-3 (2009), edited by A. N. Carvalho, H. M. Rodrigues, G. Raugel, G. R. Sell, and Y. Yi) dedicated to his 80^th birthday.

What has made Jack such an admirable person goes far beyond his professional achievement. Being a student, a colleague, and a close friend of him for the past twenty years, I have had a great honor to witness his remarkable professionalism and dedication to work, his unselfishness and thoughtfulness to people, and his principle and persistence toward life. He never stopped working and helping the community and others even during the last remaining months of his life while battling with a severe illness. In the forthcoming JDDE Special Issue 22 No 1 (2009), one can find a beautiful work which Jack finished with Genevieve Raugel during that difficult period. For other information on Jack’s career experiences, his legendary life, and his unique character, I would like to mention the recent obituary article written by Shui-Nee Chow and John Mallet-Paret to appear in the JDDE Special Issue 22 No 2 (2009) which will also be re-published in the upcoming issue of SIAM DSWeb Magazine. I also would like to recall my 2003 interview with Jack for the SIAM DSWeb (link).

There are just too many things to write about Jack, and the above is only a short summary of some references about his career and life. During the last few months, I have been thinking of writing a tribute/memorial article about Jack. But I finally realized that this is an impossible task exceeding my own ability and knowledge.  I thus hope that there will be an opportunity some day for many of us to take the task together – this will not only be the best memento for Jack but also a valuable effort to document an important part of the history of modern dynamics.

To this end, I would like to borrow a nick name which George Sell has long used for Jack: "The Grand Attractor". To me and, I am sure to many who love him, this is the best short description about Jack both as an outstanding scholar in our time as well as a superior person -- his fundamental role played to the development of the area of dissipative dynamics and further to the entire field, as well as his attraction to and tremendous impacts on many of us around the world.