"I'm turning 70 on May 1 and I'm retiring on the 15th of May, so this time Robin asked if we could have a lecture around the 1st of May and she said she knew exactly who she wanted to get," Robert Fossum said.

Fossum's choice for speaker was fitting: a world-renowned mathematician and physicist from Harvard named Arthur Jaffe whose many honors include being past president of the American Mathematical Society (AMS). The Lecture Series has had speakers from top-level Microsoft executives to nationally-known cognitive scientists, but the choice of an imminent mathematician was a personal one for Fossum. He is retiring after a long career that saw him make major contributions to the Illinois Department of Mathematics and to the field of mathematics through his research and work with AMS.

Fossum grew up in Northfield, Minnesota, famous for thwarting a daring 1876 bank robbery that spelled the beginning of the end for the James gang, and for being home to two well-respected small colleges. His father ran the school's bookstore at St. Olaf's College and his uncle was chair of the college's physics department.

"It was very intellectually stimulating," Fossum said of his childhood environment.

"The bookstore at that time was in the St. Olaf College library building and he had keys to every place there, so I would go up there on Saturdays with him and go back into stacks of the library. It wasn't like it is today with security; I had total access to everything in that library."

It was there that Fossum began exploring his intellectual and scientific interests. A master key to the physics building courtesy of his uncle helped him unlock the door to applications.

"I had access to the machine shop and the classrooms and all of the laboratories," he said. "I probably didn't make the best use of it, but my friends and I around '55 or '56 used the physics lab to make rockets."

Using the machine shop's lathe, some pipe, and some homemade gunpowder, Fossum and his high school buddies began their own rocket program.

"One of the guys was a chemist and he would make gunpowder and we'd fill these things with gunpowder and an old flash bulb that we had broken the glass out of and stand a ways away, connect to the battery, and watch these things go aloft," Fossum said with a laugh. "Nowadays we would be declared terrorists."

Fossum's scientifically adventurous sprit didn't end there: he earned a Ph.D. in Mathematics from Michigan before joining the faculty at Illinois in 1964. It was early in his career here that Fossum learned about the Fulbright Scholar program, an international exchange program that allows American faculty members to teach and learn abroad. Both sets of his grandparents were born in Norway, so he applied for and was accepted for a year teaching at the University of Oslo.

"They asked me to stay another year as a visiting professor and I told them I would stay another year as a janitor," Fossum said. "The advantage was I got to meet a lot of people, not just in Norway but all over Europe."

Fossum's European adventure continued off and on for the next decade - taking leaves of absence without pay from Illinois - and included faculty positions in Denmark and France as well as Norway. The experience benefitted not only Fossum but also the University of Illinois and the field of mathematics.

"I think all of these contacts are what really made my career," he said. "It was well worth it because I was bringing back ideas to our campus too. I would come back and lecture and give seminars on the material that I learned."

A few years later those contacts also helped Fossum in his efforts to expand the American Mathematical Society into a truly international organization while serving as its secretary for a decade. Sheldon Katz, Chairman of the Illinois Department of Mathematics, said Fossum's tenure as secretary from 1989 to 1999 was important because of the part he played while AMS's publishing services operations were being doubled and Webbased services were introduced.

"He was an important player in the profession," Katz said. "The Secretary is one of the most important leadership positions in the Society and critical for continuity - Robert was only the eighth Secretary in the 120-year history of the AMS. Throughout his service to the Society, he liked to take risks while pursuing enormous benefits. In a similar vein, he currently chairs the math department's newly formed Online Committee, a policy and oversight committee for our online offerings."

Through his European contacts, Fossum began turning AMS meetings into international events.

"The American Mathematical Society is the largest professional organization for research mathematicians," Fossum said. "The contacts I had were very important. I knew all the important people in Europe to discuss this with so there were no problems with doors being opened," he said.

Fossum also knew the value of sound diplomacy.

"We had members all over the world so why shouldn't we have meetings in Germany, for instance," he said. "But we couldn't just walk into Germany and have a meeting because the Germans have a mathematical society. So what I did was arrange for the host country's mathematical society to have a joint meeting that was sponsored.

"Of course I was always very careful about saying this is a collaborative thing, let's do it together. That was very important. Now there are probably four a year, one with Mexico, in China, Australia, India, worldwide. I started that and I'm really proud of it."

Fossum's research interests are in algebraic groups, classical invariant theory, and applications of geometry and algebra to computer vision. He lists a paper called Vector bundles over spheres are algebraic as his favorite and a book titled The Divisor Class Group of a Krull Domain as a text he's most proud of because it became a main reference in the area of commutative rings and ideal class groups.

At Beckman, Fossum is a member of the Image Formation and Processing group, where he works with researchers Tom Huang and Yi Ma, contributing mathematics to projects involving topics like face recognition and segmentation and clustering of images.

"One of the ways that mathematics gets involved is in describing things using algebraic equations," Fossum said. "Another way is to try and find the components of the image that satisfy certain equations. You're telling this (face recognition) software what to look for and one of the things it is looking for is these equations. I'm not a programmer but I can say look for these equations and the graduate students are very good programmers so they say 'I know how to do that.'"

Even though Fossum came to Beckman later in his academic career, he said it has been a great learning experience.

"Until I came to Beckman I had been considered a pure mathematician and the work that I was doing was definitely not influenced by any engineering applications," he said. "So I think that it's really opened up my own eyes to the way mathematics can help solve engineering problems and, on the other hand, many mathematics problems that arise from engineering problems can be solved. I came over to Beckman in 2000 and I think it has completely changed my point of view on the importance of interdisciplinary work."

Even though he is retiring, Fossum still hopes to keep working at his office at Beckman and he and his wife plan on continuing to fund the lecture series. He said the Robert and Robin Fossum Distinguished Lecture Series grew out of a discussion with Institute Director Pierre Wiltzius about Fossum's desire to give something back to Beckman.

"I was really appreciative of being able to come over to Beckman," he said. "I think I'm the first mathematician who has had a full appointment here. I was really proud of that. We give this money and we plan to continue on giving this money because I think it's important for the Institute. It brings people here who maybe wouldn't normally come."

The Fossums have a second home on five wooded acres in northern Wisconsin, near his father's boyhood home, but Robert doesn't plan on complete retirement just yet. He wants to continue working on projects, while his wife Robin continues to serve as a Senior Regional Director of Gift Development for the University of Illinois Foundation.

"Most of what she does is stewardship," Robert said. "I grew up in the Lutheran Church and I can remember one of the things they taught was stewardship. Officers practice stewardship and part of that is thanking people all the time, even for the smallest, smallest gift because you never know when that is going to multiply."

While he doesn't mind being thanked, Fossum said he and his wife fund the lecture series for other reasons.

"I don't need to have my back scratched," he said. "I give money for something like this because I think it's valuable."

The Fossums keep framed posters, signed by the speaker, of each of the series' lectures in their home. It's safe to say the poster for Jaffe lecture will have some extra meaning for them.

"I think he'll give a very good lecture," Fossum said. "I'm just very pleased that he's coming because we asked him to come."