  Dark energy in the universe is assumed to be vacuum energy. The
energy-momentum of vacuum is described by a scale-dependent cosmological
constant. The equations of motion imply for the density of matter (dust) the
sum of the usual matter density (luminous matter) and an additional matter
density (dark matter) similar to the dark energy. The scale-dependent
cosmological constant is given up to an exponent which is approximated by the
experimentally decided density parameters of dark matter and dark energy. This
yields that dark matter is one third of dark energy for all times implying an
explanation of the coincidence of dark matter and dark energy. In the final
state, the universe becomes dark, consisting of dark matter and dark energy.
