Linear perturbations on the cosmological background in the relativistic theory of gravitation: I. Theory

We have derived a system of second-order ordinary differential equations to describe the evolution of small perturbations in the gravitational field and matter characteristics in RTG, with the cosmological solution being a background. These equations are shown to admit the effective gauge invariance, since the graviton mass can be neglected in most cases of interest. The standard expansion in scalar, vector, and tensor components is performed. The equations have been derived for each component.