Affiliation: | (1) Institut für Angewandte Mathematik, Universität Bonn, Wegelerstr. 6, D-53115 Bonn, Germany;(2) SFB 611, Bonn, BiBoS, Bielefeld, Bonn, Germany;(3) IZKS, Bonn, Germany;(4) CERFIM, Locarno and Acc. Arch. (USI), Switzerland;(5) National Technical Uni., Kyiv, Ukraine;(6) Institute of Mathematics, Kyiv, Ukraine |