Hard diffractive scattering: partons and QCD
  The HERA diffractive structure function data are interpreted in terms of `diffractive parton distributions' which satisfy DGLAP evolution. These distributions are modeled assuming that the scattering takes place off a colour singlet `pomeron' target. A quantitative test of the universality of diffractive parton distributions is proposed. 
Z. Kunszt (ETH, Zurich), W. J. Stirling (Durham)