In March 2004, an international conference was held in Vienna, Austria, on the occasion
of the retirement of Heinz Langer, one of the leading experts in operator theory
of indefinite inner product spaces. This volume contains some of the papers presented
at the meeting. These fifteen refereed articles report on recent and original results in
various areas of operator theory, all of them related with the work of Heinz Langer. The
topics range from abstract spectral theory in Krein spaces to more concrete applications, e.g., to boundary value problems, the study of orthogonal functions or moment problems.
The book closes with a historical survey paper.
The scientific part of the book is preceeded by some biographical material and some information about the conference itself. This includes the conference program, the list of participants and an updated list of publications of Heinz Langer.