Affiliation: | (1) Dipartimento di Informatica e Sistemistica, Università di Roma ``La Sapienza,' Via Buonarroti 12, I-00185 Roma, Italy soler@dis.uniroma1.it , IT;(2) Department of Mathematics, University of Dortmund, 44221 Dortmund, Germany fischer@math.uni-dortmund.de , DE;(3) Institute of Applied Mathematics, University of Hamburg, Bundesstrasse 55, D-20146 Hamburg, Germany kanzow@math.uni-hamburg.de , DE;(4) State Key Laboratory of Scientific and Engineering Computing, Academia Sinica, P.O. Box 2719, Beijing, 100080, People's Republic of China pjm@lsec.cc.ac.cn , CN |