Fourth Bar-Ilan-Ulm-Workshop in Mathematics: workshop proceedings, Ulm, June 29 - July 1, 1998

This booklet contains papers and abstract of talks presented at the fourth Bar-Ilan-Ulm-Workshop organized by the Faculty of Mathematics and Economics of the University of Vim, June 29 - July 1, 1998. Since 1992 the two Departments of Mathematics at the Bar-Ilan University (Ramat Gan, Israel) and at the University of Ulm (Ulm, Germany) have had an ongoing cooperation with joint research projects and a series of workshops organized alternately by the departments, the last one in 1994. The purpose of this workshop was on one hand to make it possible to exchange ideas and thoughts in mathematics and on the other hand to give the new members ofthe departments the chance to join the cooperation. Besides the colleagues from Israel we were happy to host German colleagues from Freiburg, Halle and Würzburg and visitors of our Department of Mathematics in Ulm. The main topics in the workshop where Analysis and Algebra/Number Theory. We thank the Forschungszentrum Jülich GmbH, ÖA-IB, funded by the Federal Ministry of Education, Science, Research and Technology (BMBF), the Ulmer Universitatsgesellschaft and the Rector of the University of Ulm for financial and ideal support. Furthermore we thank all our guests and colleagues for coming, contributing interesting mathematics and creating a very pleasant atmosphere