  A polarization of the Lie algebras $Map(C, G)$ of gauge transformations on
the light-cone $C\subset\RM^4$ is introduced, using splitting of the initial
data on $C$ for the wave operator to positive and negative frequencies. This
generalizes the usual polarization of affine Kac-Moody algebras to positive and
negative frequencies and paves the way to a generalization of the highest
weight theory to the $3+1$ dimensional setting.
