Beschreibung
Autorenporträt
(1) Marek Golasinski Institute of Mathematics Casimir the Great University pl. Weyssenhoffa 11 85-07 2 Bydgoszcz, Poland e-mail: marek@ukw.edu.pl (2) Juno Mukai Shinshu University Matsumoto, Nagano Pref. 390-8621, Japan e-mail: jmukai@shinshu-u.ac.jp