Introduction

Abstract

As organizer of this meeting I welcome you and hope that your stay will be pleasent and profitable for you. Many of you have attended one of the past Schladming-meetings and will have noticed that we were able to expand this meeting from a rather small scale event to a respectable conference. There is, however, always the serious problem, how such a meeting should be arranged especially when one considers that the number of participants has almost doubled every year. This year we have tried to split the meeting into two parts: the first part is ment to outline the general background of the more sophisticated lectures of the second part. The success of this meeting will show whether this was a good idea.