The purpose of this publication is to present, in one book, various
approaches to analytic problems that arise in the context of singular
spaces. It is based on the workshop 'Approaches to Singular Analysis'
which was held on April 8-10, 1999, at Humboldt University of Berlin.
The aim of this workshop was to bring together young mathematicians
interested in partial differential operators on singular con-
figurations. The main idea was to look at different approaches that have
been proposed, and try to understand to which extent they overlap and
how they differ. The workshop took place in a rather relaxed atmosphere.
The participants appreciated that there was a discussion session every
day, which gave a lot of room for an open exchange of ideas. This book
contains articles by workshop participants and invited contributions.
The former are expanded versions of talks at the workshop; they give
introductions to various pseudodifferential calculi and discussions of
relations between them. In addition, we invited a limited number of
papers from mathematicians who have made significant contributions to
this field. Unfortunately, several of these invita- tions were turned
down due to other commitments. For this reason, only a very small number
of contributions from non-participants remain. The absence of any
particular name from the list of (invited) contributors should not be
interpreted as a bias of the editors against that scientist. It rather
reflects our restricted choice of invitations due to lack of space.