First Author:   Ken-ichi Hashimoto Graduate School of Economic, Kobe University hashimoto@econ.kobe-u.ac.jp   Rokko-dai 2-1 Kobe, 657-8501, JAPAN       Second Author: Taro Kumagai Graduate School of Economic, Kobe University kumataro@kuma-taro.com   Rokko-dai 2-1 Kobe, 657-8501, JAPAN