Theorems of factorising matrix functions and the operator identity method play an essential role in this book in constructing the spectral theory (direct and in

Canonical systems occupy a central position in the spectral theory of second order differential operators. They may be used to realize arbitrary spectral data,

An essentially self-contained treatment ideal for mathematicians, physicists or engineers whose research is connected with inverse problems.

This volume, which is dedicated to Heinz Langer, includes biographical material and carefully selected papers. Heinz Langer has made fundamental contributions t

The focus program on Analytic Function Spaces and their Applications took place at Fields Institute from July 1st to December 31st, 2021. Hilbert spaces of anal