Spectral Theory and Wave Processes

Transition of the Quasi-Levels in the Discrete Spectrum of the Schrödinger Operator under Strong Perturbations of the Potential.- A Criterion for the Existence of the Complete Wave Operators in the Theory of Scattering with Two Spaces.- The Inverse Problem for the Wave Equation with an Unknown Source.- On the Various Formulations of the One-Dimensional Inverse Problem for the Telegraph Equation.- Quantitative Characteristics of Singular Measures.- Spectral Identities and the Trace Formula in the Friedrichs Model.- Perturbation of the Spectrum of the One-Dimensional Self-Adjoint Schrödinger Operator with a Periodic Potential.- The Field of a Point Source Located Outside a Convex Curve.- Criteria for the Boundedness and Complete Continuity of Certain Imbedding Operators.- A Uniqueness Theorem for Functions with Positive Imaginary Part.- Application of the Method of Standard Comparison Problems to Perturbations of the Coulomb Field. The Discrete Spectrum.