Low-frequency asymptotic behavior of the Green's functions of degenerate Bose systems (kinetic approximation)

On the basis of Bogolyubov's idea of a reduction in the description of nonequilibrium states, a closed system of equations is obtained for investigating the behavior of a spatially inhomogeneous degenerate system of Bose particles with weak interaction in the presence of an external alternating field. The connection between the low-frequency asymptotic behavior of the Green's functions and the kinetic characteristics of the system is established.