Affiliation: | 1. Division of Mathematics and Physics, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan;2. Faculty of Mathematics and Natural Sciences, Universitas Tanjungpura, Pontianak, Kalimantan Barat 78115, Indonesia;3. Faculty of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan |