Institution: | (1) Department of Mathematical Information Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162–8601, Japan;(2) The Research Institute of Educational Development, Tokai University, 2-28-4 Tomigaya, Shibuya-ku, Tokyo 151–8677, Japan;(3) Department of Mathematics, Asahi University, Hozumi, Gifu 223–8522, Japan;(4) Department of Mathematics, College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101–8303, Japan |