Institution: | Y Centre for Mathematical Analysis and its Applications, University of Sussex, Falmer, Brighton BN1 9QH, UK E-mail: d.e.edmunds@sussex.ac.uk W Department of Mathematics, Czech University of Agriculture, 16521 Prague 6, Czech Republic E-mail: gurka@tf.czu.cz X Mathematical Institute, Academy of Sciences of the Czech Republic, Zitná 25, 11567 Prague 1, Czech Republic E-mail: opic@math.cas.cz |