Measurements of the Structure of Diffraction at HERA
  Measurements of diffraction in electron-proton collisions are presented. All measured processes which occur through the exchange of a virtual photon (DIS) are consistent with a universal structure. For the diffractive photoproduction of dijets, factorisation is broken by a global factor ~0.5 with respect to the DIS processes. 
Sebastian Sch\"atzel (for the H1 and ZEUS Collaborations)