新板 窮理図解

While mathematicians today are in great demand by businesses, it is said finding employment is difficult for mathematics researchers
      Because securing a post as a mathematics researcher is highly competitive, one needs good timing and luck in addition to ability. When I completed the doctoral course, an increasing number of young people wanted to become researchers but the number of posts available was on the decrease. Naturally, they were faced with keen competition. In my case, following the service with the Hokkaido University, I had to serve as a PD at the University of Tokyo for half a year then at the University of Toronto. Since I got a preliminary offer for a post from Keio just before leaving for Toronto, I put an end to my six months of stay in Toronto much earlier than the initial plan. In April 2008, I reported to Keio University Department of Mathematics, Faculty of Science and Technology as an assistant professor. Because I was able to find employment with such a highly reputable university as Keio, I feel the five years of my PD period were not useless after all. After assuming a post with Keio, I also had a chance to study at the University of Denmark.
      A good thing about Keio University Faculty of Science and Technology lies in that the relation between teachers and students is close, reflecting the Keio policy of “Half Learning, Half Teaching.” When it comes to study we have hot discussions, but enjoy sake together at other times in an at-home atmosphere, which I like very much. Unlike mathematics departments of other universities (Japanese or overseas) I know, Keio’s Department of Mathematics not only pursues pure theories of mathematics but also emphasizes application aspects of this study. Of our students, only a few become mathematics researchers after graduation. Their future courses are diverse, some becoming school teachers and others finding employment with businesses and so on. At Keio, interactions among teachers from various departments, such as labs specializing in statistics and computer sciences, are also active. Speaking of myself, I feel my field of vision has expanded considerably thanks to such an open culture.

Do you sometimes engage in joint researches yourself?
      Yes. I studied alone in the beginning. But while I was in Toronto, a set theory specialist, who had read my paper, visited my office and offered a joint research on a certain problem. It was a difficult problem left unsolved for 30 to 40 years. By joining forces, however, we could solve that problem. Since that time, I’m willing to call out to other researchers when I feel joint research approach would be better.

On what occasions do you usually get inspiration?
      When trying to solve problems, the first thing I do is find out things in common in several instances and phenomena and then arrange them in writing. Thinking it over for some time, there may come a moment of inspiration while I’m relaxing. Or it may come while I’m taking a shower, or walking. Such moments vary according to the situation. One day I suddenly got an inspiration. So excited with joy, I phoned up my co-researcher in spite of myself.
      This is why the existence of my family, with whom I can relax in comfort, is so important. I have a family of four: my wife who is my good supporter, the first son who is an elementary school third grader, and the second son who is a preschool senior class student. The first son is already a third grade rank holder in the game of Go, the same level as me. He defeats me at times (Laughter). He was even chosen as a Go representative for Kanagawa Prefecture. The second son loves playing board games just like myself and is getting stronger and stronger. I’m proud of him and looking forward to his future.

Some words from students
Student : I joined the Katsura lab simply because Dr. Katsura’s class lectures were overwhelmingly interesting, where I could image even difficult problems in an understandable way. It’s a tough requirement that we shouldn’t look at notebooks when speaking in seminars. But this rule helps me a lot in understanding things accurately and speaking logically in public.

(Reporter & text writer: Madoka Tainaka)