  Transverse and longitudinal electroweak gauge boson parton distribution
functions (PDFs) are computed in terms of deep-inelastic scattering structure
functions, following the recently developed method to determine the photon PDF.
The calculation provides initial conditions at the electroweak scale for PDF
evolution to higher energies. Numerical results for the $W^\pm$ and $Z$
transverse, longitudinal and polarized PDFs, as well as the $\gamma Z$
transverse and polarized PDFs are presented.
