Institution: | Department of Mathematics, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-8610, Japan ; Department of Mathematics, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-8610, Japan Ray Redheffer ; Department of Mathematics, University of California, Los Angeles, California 90095-1555 |