 Light-cone gauge for a two-form

When ${\partial }_{-}$ is invertible, choose $B_{-m}=0$. Residual gauge parameters are exact one-forms and act trivially on $B$. The remaining independent modes are antisymmetric transverse components $B_{IJ}$, satisfying $\square B_{IJ}=0$; longitudinal components obey $B_{+I}={\partial }_{-}^{-1}{\partial }^J{B}_{IJ}$. There are $(D-2)(D-3)/2$ physical polarizations.