[en] The construction of the Green functions by the additive splitting of operators is described. Examples of the Green function construction for evolution and one-velocity kinetic equations are given. The results obtained are the detailing and generalization of the known perturbation theory results of higher orders. However, here underlined is their applicability as universal means for the construction of the inverse operators - Green functions, but not only as means for determining corrections as this is interpreted in the perturbation theory