Calculation of correlation functions in the case of degeneracy of the state of statistical equilibrium

General procedure of constructing the solutions of systems of equations for normal and anomalous correlation functions is developed. Approximate solutions valid in the whole time interval from $t=0$ to infinity are found in general form. For the case of superconductive model based on the Frohlich hamiltonian, energy of elementary excitations and damping are calculated and asymptotic expressions for correlation functions at large and small values of the time are obtained.