Discrete Applied Mathematics

Editor-in-Chief Endre Boros RUTCOR, Rutgers University, 640 Bartholomew Rd, Piscataway, NJ 08854-8003, USA, Founder Peter L. Hammer , Associate Editors M.F. Anjos GERAD and Dept. of Mathematics and Industrial Engineering, École Polytechnique de Montréal, CP 6079, succ. Centre-ville, Montréal, QC H3C 3A7, Canada, W. Kubiak Fac. of Business Administration, Memorial University of Newfoundland, St. John's, NL A1B 3X5, Canada, V. Lozin Mathematics Inst., University of Warwick, Zeeman Building Gibbet Hill Road, Coventry, CV4 7AL, UK, D. de Werra Dept. de Mathematiques, École Polytechnique Fédérale de Lausanne (EPFL), MA Ecublens, CH-1015 Lausanne, Switzerland, Advisory Editors E. Balas Dept. of Mathematical Sciences, Carnegie Mellon University, Pittsburgh, PA 15213-3890, USA, T. Ibaraki Dept. of Informatics, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, 669-1337 Sanda-Shi, Japan, D.J. Kleitman Dept. of Mathematics, Massachusetts Institute of Technology (MIT), 77 Massachusetts Avenue, Cambridge, MA 02139, USA, B. Korte Research Inst. for Discrete Mathematics Rheinische Friedrich-Wilhelms-Universität Bonn, Lennéstr. 2, 53113 Bonn, Germany, Board of Editors N. Alon Sackler Fac. of Exact Sciences, Tel Aviv University, Ramat-Aviv, 69978 Tel Aviv, Israel, M. Anthony Dept. of Mathematics, London School of Economics, Houghton Street, Houghton, London, WC2A 2AE, UK, D. Avis School of Computer Science, McGill University, 3480 University Street, Montreal, QC, H3A 2A7, Canada, J.-C. Bermond Mascotte, joint project I3S (CNRS-UNS)/INRIA, Institut National de Recherche en Informatique et en Automatique (INRIA), 2004 Route des Lucioles, BP 93, F-06902 Sophia-Antipolis, France, A. Brandstädt Fachbereich Informatik, Universität Rostock, Albert-Einstein-Str. 21, 18059 Rostock, Germany, R.E. Burkard Inst. für Mathematik, Technische Universität Graz, Steyergasse 30, A-8010 Graz, Austria, X. Chen Google, Inc., 76 9th Ave, New York, NY 10011, USA, V. Chvátal Dept. of Computer Science & Software Engineering, CENPARMI, Building EV, Concordia University, Suite 3-105, 1455 de Maisonneuve Blvd West, Montréal, QC H3G 1M8, Canada, D.G. Corneil Dept. of Computer Science, University of Toronto, 6 King's College Road, Pratt Building, Room PT398A, Toronto, ON M5S 3H5, Canada, D. Coudert Mascotte, joint project I3S(CNRS/UNS)/INRIA, Institut National de Recherche en Informatique et en Automatique (INRIA), 2004 route des Lucioles, B.P. 93, 06902 Sophia Antipolis, France, A. Deza Dept. of Computing and Software, McMaster University, 1280 Main St. West, Hamilton, L8S 4L7, ON, Canada, S. Fujishige Research Inst. for Mathematical Sciences, Kyoto University, 606-8502 Kyoto, Japan, F. Giannessi Dipto. di Matematica 'L. Tonelli', Università di Pisa, Largo Bruno Pentecorvo, 5, 56127 Pisa, Italy, M.C. Golumbic Dept. of Maths & Computer Science, University of Haifa, Mt. Carmel, Haifa, Israel, R.L. Graham Dept. of Computer Science & Engineering, University of California at San Diego (UCSD), 9500 Gilman Drive, Mail Code 0404, La Jolla, CA 92093-0404, USA, P. Hansen GERAD- HEC Montreal, 3000 Chemin de la Cote, Sainte-Catherine, Montreal H3T 2A7, Canada, P. Hell School of Computing Science, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, BC, Canada, A.J. Hoffman IBM Thomas J. Watson Research Center, 1101 Kitchawan Road, Route 134, Yorktown Heights, NY, 10598, USA, R.M. Karp Dept. of Electrical Engineering & Computer Sciences, University of California at Berkeley, Soda Hall # 1776, Berkeley, CA 94720-1776, USA, R. Klasing CNRS, LaBRI, Université de Bordeaux 1, 351 cours de la Libération, 33405 Talence, France, S. Klavzar Fac. of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia, J. Lee Dept. of Industrial and Operations Engineering, University of Michigan, 1205 Beal Avenue, Ann Arbor, MI, 48109-2117, USA, L Liberti LIX, Ecole Polytechnique, route de Saclay, 91128 Palaiseau, France, L. Lovász Theory Group, Microsoft Research, One Microsoft Way, Redmond WA 98052-6399, USA, F. Maffioli Dipart. di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy, S. Martello DEIS, Università di Bologna, viale Del Risorgimento 2, 40136 Bologna, Italy, C. McDiarmid Dept. of Statistics, University of Oxford, 1 South Parks Road, Oxford, OX1 3TG, UK, N. Megiddo IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA, R.H. Möhring Fachbereich Mathematik (MA 6-1), Technisch