The dark matter and the condensed description by the gravitational fields in the field theory

In this work the approach for a description of the physical systems about whiches it is not possible to get basicly the total information is suggested. As a result the differential equations, the solutions of which characterize the physical system, must bieng obtained from the demand of the minimality of the generalized variance. As the understanding of the particles trajectory absents in the quantum theory we shall consider that the Riemannian space-time is the effective one, postulating the metric tensor on the base of the reduced density matrix of the gravitational fields.