  A simple model of a vibrated granular monolayer is studied. It consists of
inelastic hard spheres confined between two parallel hard plates separated a
distance smaller than twice the diameter of the particles. Both walls are
elastic and one of them is vibrating in a sawtooth way. For low densities, a
kinetic equation is proposed from which closed evolution equations for the
horizontal and vertical temperatures are derived assuming spatial homogeneity
and that the system is very thin. An excellent agreement between the
theoretical predictions and Molecular Dynamics simulation results is obtained
both, for the stationary values and for the dynamics of the temperatures.
