The European Journal of Combinatorics is an international, bimonthly journal of pure mathematics, specializing in theories arising from combinatorial problems. The journal is primarily open to papers dealing with mathematical structures within combinatorics and/or establishing direct links between combinatorics and other branches of mathematics and the theories of computing. The journal includes full-length research papers, short notes, and research problems on important topics. Editors, M. Deza and M. Las Vergnas, CNRS, Ecole Normale Superieure, Paris, France and P. Rosenstiehl, Centre de Mathematique Sociale, EHESS, Paris, France.