Relativistic theory of gravitation and cosmic vacuum

Equations of the Relativistic Theory of Gravitation (RTG), taking into account the existence of a vacuum with positive constant energy density in the event space, are derived on the basis of a variational principle. In a homogeneous and isotropic event space, the deceleration parameter of the Universe is calculated, and a constraint on the cosmological constant value providing the presently observed accelerated expansion of the Universe, is found. In the theory under study, both monotonic and oscillating solutions for the scale factor are possible.