  We consider the evolution of a parton system which is formed at the central
rapidity region just after an ultrarelativistic heavy ion collision. The
evolution of the system, which is composed of gluons, quarks and antiquarks, is
described by a relativistic Boltzmann equations with collision terms including
radiation and retardation effects. The equations are solved by the test
particle method using Monte-Carlo sampling. Our simulations do not show any
evidence of kinetic equilibration, unless the cross sections are artificially
increased to unrealistically large values.
