Translation of: Rasprostranenie voln.

Includes bibliographical references.

Perturbation theory for phase integrals and its application to problems of wave propagation;Whitham's and Fermat's principles for the problem of evolution of wave beams in a nonlinear inhomogeneous medium;The splitting of separatrices for a standard family of area-preserving transformations;Boundary layer of eigenfunctions of a diffusion operator;Neutron scattering by a point nucleus in a random magnetic field. I;The splitting of eigenvalues in a double potential well under a partial breaking of symmetry;A general scheme in the stationary scattering theory;Coulomb effects in systems of several particles;On the conditions for existence of wave operators in the nonselfadjoint case;A crystal model consisting of potentials of zero radius with inner structure;Representations of ^* algebras generated by pseudodifferential operators in weighted spaces;The trace formula for the nonlinear Klein-Gordon equation;On asymptotics of the solution of the Cauchy problem for the modified Korteweg-de Vries equation;Symmetric reductions of the Riemann theta function and some of their applications to the Schr�odinger and Boussinesq equations;Large time asymptotic behavior of solutions of the Cauchy problem for a system of the KdV type with rapidly decaying nonsoliton initial data