[No. 118] Ushio Sumita
Participant Profile
Ushio Sumita
(Graduate of Tokyo Metropolitan Meisei High School) March 1973 Graduated from the Department of Industrial and Systems Engineering, Faculty of Engineering, Keio University September 1974 Joined Xerox Corporation in the U.S. as a Systems Analyst June 1979 Completed the Master's Program at the Simon Business School, University of Rochester, U.S. September 1980 Visiting Researcher at Massachusetts Institute of Technology June 1981 Completed the Doctoral Programs at the University of Rochester Assistant Professor at the College of Engineering, Syracuse University July 1982 Assistant Professor at the Simon Business School, University of Rochester April 1987 Associate Professor at the Simon Business School, University of Rochester July 1991 Professor at the Graduate School of International Management, International University of Japan Guest Professor at the Simon Business School, University of Rochester Guest Professor at the Stern School of Business, New York University July 1995 Dean and Professor at the Graduate School of International Management, International University of Japan July 2001 Professor at the Graduate School of Systems and Information Engineering, University of Tsukuba (current position)
Ushio Sumita
(Graduate of Tokyo Metropolitan Meisei High School) March 1973 Graduated from the Department of Industrial and Systems Engineering, Faculty of Engineering, Keio University September 1974 Joined Xerox Corporation in the U.S. as a Systems Analyst June 1979 Completed the Master's Program at the Simon Business School, University of Rochester, U.S. September 1980 Visiting Researcher at Massachusetts Institute of Technology June 1981 Completed the Doctoral Programs at the University of Rochester Assistant Professor at the College of Engineering, Syracuse University July 1982 Assistant Professor at the Simon Business School, University of Rochester April 1987 Associate Professor at the Simon Business School, University of Rochester July 1991 Professor at the Graduate School of International Management, International University of Japan Guest Professor at the Simon Business School, University of Rochester Guest Professor at the Stern School of Business, New York University July 1995 Dean and Professor at the Graduate School of International Management, International University of Japan July 2001 Professor at the Graduate School of Systems and Information Engineering, University of Tsukuba (current position)
The Essence of Learning Drilled into Me in the Sekine-Nishino Laboratory
As a student in the Department of Industrial and Systems Engineering at Keio University during my youth, a time when the Japanese economy was transitioning from its high-growth period to the cusp of maturity, I believe I valued a "physical way of thinking"—questioning all authority, first tackling things head-on, and only then thinking them through. The campus was far from a calm learning environment, with one strike after another. I took to the streets, and while experiencing some painful and frightening moments, I dreamed of changing the world by changing myself.
Although I was a delinquent student who rarely attended lectures, I was so captivated by the fascinating content of Professor Sekine's mathematical programming and Professor Nishino's mathematical economics that I attended every class. When I advanced to my fourth year, I knocked on the door of the Sekine-Nishino Laboratory without hesitation. The first problem I was given was, "Prove the continuity of the inner product function." I thought I could find the answer by looking in a textbook, but I understood that this was a test of my ability to build up logical reasoning. Without looking at anything, I spent three days and completed the proof on my own. In the subsequent seminars, the two professors consistently adhered to the principle of actively participating in forward-looking discussions but expecting us to review backward-looking content on our own. I was surprised and encouraged by their teaching method of "making us learn by not teaching."
Preparing for my presentation for the first summer training camp was the most grueling intellectual struggle I have ever experienced. In early June, I was instructed to understand and present on Scarf's algorithm for finding Brouwer's fixed point and was handed the appendix of Arrow's famous book, "General Competitive Analysis." I turned pale just flipping through it. Professor Arrow's notation was completely different from the papers we had covered in our seminars, and I couldn't see how the content was related at all. To give you an idea of how naively incompetent I was, I didn't even know that the English for *naiten* (内点) was "interior point," and I wondered why this mathematical content was related to interior design.
With less than two months until the summer training camp, I was at a loss. I realized I didn't understand fixed points at all and decided to take a major detour. First, I scoured the literature on fixed points and managed to get through the proof of the fixed-point theorem for contraction mappings. From there, why did Brouwer's fixed-point theorem suddenly become so difficult? "Visualize it, visualize it," I told myself, imagining two identical circular maps stacked on top of each other, where rotating one arbitrarily would always result in at least one point being in the exact same location on both maps. But I had no idea why that would be the case. I set Scarf's algorithm aside for the moment and decided to try to understand the proof of the existence theorem. Searching for literature in the library, I found a paper by Debreu published in *Econometrica*. The paper's theme was extending the Perron-Frobenius theorem through the spectral analysis of non-negative matrices, but it also provided a proof of Brouwer's fixed-point theorem as an application. I read it through until I felt I understood it, which put my mind considerably at ease. Although I had already spent a month, the rest was smooth sailing. I finished my notes three days before we left for the summer training camp.
My presentation at the summer training camp in Hachioji began at 9:00 a.m. It continued endlessly, with breaks for lunch and dinner. There were no moments where I was stuck in silence, unable to answer a question, as had happened before. I paced energetically in front of the blackboard, talking nonstop, driven by a fighting spirit that said, "I worked this hard, so you're going to listen whether you like it or not." After 2:00 a.m., as the end of my talk finally came into sight, even the unflappable Professor Sekine said, "Sumita, that's enough. The rest is just such-and-such, right? I'm tired." Then Professor Nishino added, "Yes, let's wrap it up." Needless to say, I shouted "Yes!" in my mind.
This experience became the source of energy for my subsequent intellectual and creative activities. I realized that being a slow learner or having less ability is not such a bad thing. By honestly facing myself and steadily putting in the effort, I could achieve my own unique intellectual creations through a different path than that of geniuses. For example, my two brilliant professors were only interested in beautiful things and would readily discard anything that did not meet their aesthetic standards. In my case, even if a paper's content is mundane, I will improve it to a publishable level and always get it published. Through such accumulation, I aimed to produce papers with content that represented a leap forward from existing research. Furthermore, since I had spent more time on the streets than my professors, I have continued to leverage that experience, tackling the realities of social systems and management to unearth research topics.
Even now, after Professor Sekine has passed away and Professor Nishino has retired from the front lines, I continue my intellectual and creative activities while constantly holding a dialogue with them in my mind. And I am determined to pursue "lifelong intellectual creation."