MITSURU IKAWA is a Professor of Mathematics at Osaka University, Japan. The author of more than 40 professional papers and book chapters, he is a member of the Mathematical Society of Japan, and serves as editor of the Osaka Journal of Mathematics and associate editor of the Japanese Journal of Mathematics. Dr. Ikawa received the B.Sc. (1965) and M.Sc.(1967) degrees in mathematics from Kyoto University, Japan, and the Ph.D. degree (1970)in mathematics from Osaka University, Japan.