On controllability of the Navier-Stokes equations

Different statements of the controllability problem for the Navier-Stokes equations are given. Theorems on exact, on local exact and on approximate controllability of the 3D Navier-Stokes equations are obtained when control is concentrated on the boundary of a domain Ω filled by a fluid and in the case of periodic boundary conditions (i.e. these equations are defined on torus II), the control is distributed and it is concentrated in a subdomain of II