THE METHOD OF RAISING THE CONTINUOUS SPECTRUM LOWER BOUNDARY IN PROBLEMS OF SPECTRAL THEORY OF WAVEGUIDE SYSTEMS

摘要

The problem of excitation of steady-state vibrations in a waveguide has been solved. It is demonstrated that the problem, inequivalent to the above one, with the continuous spectrum lower boundary higher than that of the above one, can be used for proving its Fredholm property. The proof uses neither infinite sums, nor any specific functional spaces.