Institution: | 1. Department of Mathematics, The University of Texas–Pan American, Edinburg, TX 78539, USA; 2. Department of Mathematical Sciences, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata 990-8560, Japan; 3. Institute of Mathematics for Industry, Kyushu University, 744 Motooka, Fukuoka 819-8581, Japan; 4. Department of Mathematics, Kobe University, Rokko, Kobe 657-8501, Japan |