Pomerons and jet events at HERA

We study two and three jet events with a large rapidity gap at HERA. As a minimal model we take the coupling of the Pomeron to the quarks and gluons pointlike. This makes it relatively easy to construct a Monte Carlo program with which the model can be tested. The only degrees of freedom are the coupling constants of the Pomeron to the quarks or the gluons and a cutoff procedure to keep the Pomeron-gluon coupling well behaved. In view of the fact that –due to detector effects– in general it is rather complicated to make a detailed comparison with data, this calculation should be useful as a reference calculation for other models.