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

This is the first monograph devoted to the Sturm oscillatory theory for infinite systems of differential equations and its relations with the spectral theory. I

This book is an updated version of the classic 1987 monograph "Spectral Theory and Differential Operators".The original book was a cutting edge account of the t

These notes will be useful and of interest to mathematicians and physicists active in research as well as for students with some knowledge of the abstract theor

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