Managing Editors Shigeo Kusuoka University of Tokyo Tokyo, JAPAN Akira Yamazaki Meisei University Tokyo, JAPAN Editors Robert Anderson University of California, Berkeley Berkeley, U.S.A. Charles Castaing Universite Montpellier II Montpellier, FRANCE Frank H. Clarke Universite de Lyon I Villeurbanne, FRANCE Egbert Dierker University of Vienna Vienna, AUSTRIA Darrell Duffie Stanford University Stanford, U.S.A. Lawrence C. Evans University of California, Berkeley Berkeley, U.S.A. Takao Fujimoto Fukuoka University Fukuoka, JAPAN Jean-Michel Grandmont CREST-CNRS Malakoff, FRANCE Norimichi Hirano Yokohama National University Yokohama, JAPAN Leonid Hurwicz University of Minnesota MinneapoUs, U.S.A. Tatsuro Ichiishi Hitotsubashi University Tokyo, JAPAN Alexander loffe Israel Institute of Technology Haifa, ISRAEL Seiichi Iwamoto Kyushu University Fukuoka, JAPAN Kazuya Kamiya University of Tokyo Tokyo, JAPAN Kunio Kawamata Keio University Tokyo, JAPAN Norio Kikuchi Keio University Yokohama, JAPAN Tom M aniyama Keio University Tokyo, JAPAN Hiroshi M atano University of Tokyo Tokyo, JAPAN Kazuo Nishimura Kyoto University Kyoto, JAPAN Marcel K. Richter University of Minnesota Minneapolis, U.S.A. Yoichiro Takahashi Kyoto University Kyoto, JAPAN Michel Valadier Universite Montpellier II Montpellier, FRANCE Makoto Yano Keio University Tokyo, JAPAN