ABSTRACT
Chapter 2 is also auxiliary. It discusses some concepts and results of the spectral theory of compact operators in a Hilbert space, which will be used in this text. The major part of the chapter is devoted to the eigenvalues and singular values of Schatten - von Neumann operators, as well as to estimates for the resolvents and spectrum perturbations of these operators. The regularized characteristic determinants are also considered. By these determinants below, we investigate perturbations of the associate infinite products.
