The electromagnetic and weak structure functions of the photon can be
studied in the deep inelastic electron-photon processes e+gamma → e+X and
e+gamma → nu+X. While at low energies only virtual photon exchange is
operative in the neutral-current process, additional Z-exchange becomes
relevant for high Q2 of order MZ^2 at e+e- linear colliders. Likewise the
charged-current process can be observed at these high energy colliders. By
measuring the electroweak neutral- and charged-current structure
functions, the up- and down-type quark content of the photon can be
determined separately.
