Affiliation: | Department of Mathematics, Osaka Kyoiku University, Asahigaoka, Kashiwara, Osaka 582, Japan ; Department of Mathematics, Osaka Kyoiku University, Kashiwara, Osaka 582, Japan - permanent address: Department of Basic Science and Technology, China Textile University, Shanghai, China, Postal code 200051 Eizaburo Kamei ; Momodani Senior High School, Ikuno, Osaka 544, Japan |