Nozomu Muto Yokohama National University   79-3 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501 Japan   nozomu.muto@gmail.com   https://sites.google.com/site/nozomumuto/           JEL Areas: D4 : Market Structure and Pricing: General C7 : Game Theory and Bargaining Theory:General