Diffractive deep-inelastic events with a large rapidity gap are analyz
ed by using a Regge model for the Pomeron flux and a gluonic content f
or the Pomeron. Contrary to expectations, the simplest assumption for
the Pomeron trajectory gives the best agreement with the data on the r
atio of diffractive to total number of events. In this case the main p
roperties of the model are described by an analytic expression.