Professor at Department of Mathematics and Physics,
Faculty of Science and Technology, Hirosaki University
Address： 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
Faculty of Science and Technology, Hirosaki University
TEL:(+81)-(0)172-39-3628
e-mail: shintaro.mori^@^gmail.com (relpace ^@^ with @)