The transport equations for a two-dimensional electron gas with spin-orbit
interaction are presented. The distribution function is a 2x2-matrix in the
spin space. Particle and energy conservation laws determine the expressions for
the electric current and the energy flow. The derived transport equations are
applied to the spin-splitting of a wave packed and to the calculation of the
structure factor and the dynamic conductivity.Comment: 6 pages, 1 figure, revised versio