Institution: | (1) Mathematical Institute of the Hungarian Academy of Sciences, Budapest;(2) Institute of Operations Research, University of Bonn, Bonn, Germany;(3) Massachusetts Institute of Technology, 02139 Cambridge, MA, U.S.A.;(4) Eötvös University, Budapest;(5) University of New Mexico, Albuquerque;(6) University of Paris VII, 2 Place Jussieu, 75005 Paris, France;(7) University of California, San Diego |