Robby led a full and productive research life in which he wrote more than 50 papers and 3 books. He was a student of S.S Chern, one of the outstanding geometers of this century, who himself was, in effect, an unofficial student of the great French mathematician Elie Cartan. The works of Cartan were not always easy to understand , and Robby devoted much of his energy to explaining them, first to colleagues and students and later also to engineers working in the area of geometric control theory. Graduate education was very important to Robby, and he always seemed to be running extra seminars for graduate students, passing out lecture notes and generally operating in a gear that no one else seemed to have. He ultimately had 13 Ph.D and 18 Masters students, and he served a term as director of Graduate Studies. In 1981 he and Udo Simon, his friend and collaborator for many years, initiated a fruitful exchange program between the mathematics departments at UNC and the Technical University of Berlin that has enriched the faculty and graduate students of both departments.
Robby was one of the first people in the department to understand the important role that computers would play in mathematics, perhaps as a result of his undergraduate experiences with Von Neumann's original computer at Princeton. He was influential in upgrading the computing environment, both in the department and in the University. He bought perhaps the first home computer in the department although the way that he financed this purchase is probably not one that he would recommend to others.
Robby was a tireless traveler and probably rolled up more frequent flier miles in his life than anyone except, possibly, Captain Kirk and the crew of the Enterprise. Apart from a busy schedule of conferences and invited talks he regularly attended the annual meetings not only in mathematics but later in engineering as well. Robby certainly spent more time in the air than anyone I have ever known. He liked to tell a story that once when his son Steven was very young and Robby was out of town someone asked Steven where his daddy was. Steven thought a moment and then pointed up toward the sky with his finger.
Not all of Robby's travel time was spent on business. When traveling to Germany to visit Udo Simon, Robby would usually take along an empty suitcase or two and bring them back filled with the finest German wines, which he would offer generously to all who were interested.
Robby's interest in fine wines extended to good food and fine restaurants all over the world. However, his tastes extended to more ordinary eatables as well. Even his close friends may be unaware of his extensive potato chip collection that was on display to all who entered his office. He never revealed his master plan for these chips to me, and that will have to remain a mystery.
No discussion of Robby and transportation would be complete without some attention to the famous Gardner automotive fleet. The early cars were big, battered prize fighters that had survived the streets of New York and were ready to take on all comers in Chapel Hill. Robby was king of the road during these years and other cars gave him a wide berth. He enjoyed it thoroughly. However, he did admit that his children, Kirsten and Steven, seemed to enjoy his cars less than he did and when he dropped them off at school they asked that it be around the corner and out of sight. Robby's later cars were increasingly sophisticated Buicks that came equipped with giant instruction manuals. I used to tease him mercilessly, but he was always a good sport and on one occasion he got his revenge. I borrowed one of his cars to pick up a speaker, Jeff Cheeger, at the airport. As I stepped in, I was overwhelmed by the complexity of the dashboard and the various banks of control buttons, which contrasted sharply with the primitive technology of my old Saab. After struggling for some minutes to adjust my seat I managed to get underway and pick up Cheeger. However, as I came to the booth to pay for my parking I discovered that I had no idea which button would open my window, and I eventually tried all of them, to the amusement of the parking attendant and my passenger. Even Robby and Harolyn would sometimes have trouble controlling these cars, which had many small motors and devices that from time to time would decide to operate on their own. Harolyn was once underway in traffic when the driver's seat motor turned itself on and the seat began writhing beneath her. On another occasion Robby's unoccupied car turned on another small motor, which overheated and set the car and even a tire on fire. Some of the stories that Robby told about his cars were so bizarre that they seemed more like fiction by Stephen King than real life events.
Robby was a warrior, and I think that he enjoyed the struggle almost as much as he enjoyed winning. A famous American once said " You gotta know when to hold 'em, know when to fold 'em ", but for Robby, folding was an option that he rarely exercised.
Robby could have led a second and possibly more lucrative career as a tax consultant. He enjoyed his annual competition with the IRS and he usually began preparing in January. He armed himself with the unexpurgated version of the Federal Tax Code, and he researched all changes from the previous year. No potential tax deduction was too small to be considered. Robby was so good at tax questions that I and many others came to rely on him for advice and the correct interpretations of ambiguous instructions by the IRS. Near April 15 he and Harolyn used to answer the phone routinely with the response " H and R Gardner."
Robby had strong opinions on many subjects, and it was great fun to debate him even though no one ever won, at least in my opinion. The department will lose some of its liveliness without him. I will miss him.