Kunio Kawamata on Hugo F. Sonnenschein

The basic idea of the paper is contained in my Ph.D. thesis submitted to the University of Minnesota in 1972. I would like to mention the names of the three professors who helped me to complete the Ph.D. thesis. One is Ed Foster, who was then the chief adviser to the graduate students, and was also the co-author of the Econometrica 1970 article with Hugo upon which my paper is based. The second is Marcel Richter, the main adviser of my thesis, who read every part of my paper very carefully and gave me penetrating comments. The third person is the late Hukukane Nikaido who was then visiting Minnesota and pointed out several errors in my original draft. The name Hugo Sonnenschein was not included in the above list because he was at Northwestern when I was writing the thesis. He might not have known that my thesis was based on his paper. Still my indebtedness to him is pervasive. For me he played the role of the King of Denmark in the Shakespeare’s Hamlet; although he did not appear on the stage, the drama would not have concluded without him. I took his course in advanced Microeconomics around 1970, when some students were staging demonstration against the Vietnam War. Hugo’s class was open as scheduled but, instead of requiring us to come to the class, he gave us an option of solving some of the open problems. I do not remember whether he mentioned the problem I worked on, but the Foster and Sonnenshein paper had been published by then, and I read it with great interest. I should also mention that Hugo was then working on the celebrated Sonnenschein theorem on market excess-demand functions.