Vector field as a quintessence partner

We derive generic equations for a vector field driving the evolution of flat homogeneous isotropic universe and give a comparison with a scalar filed dynamics in the cosmology. Two exact solutions are shown as examples, which can serve to describe an inflation and a slow falling down of dynamical " cosmological constant " like it is given by the scalar quintessence. An attractive feature of vector field description is a generation of " induced mass " proportional to a Hubble constant, which results in a dynamical suppression of actual cosmological constant during the evolution.