  In this note we analyse the relation between the triple-pomeron and
Good-Walker formalisms for diffractive excitation in DIS and hadronic
collisions. In both approaches gap events are interpreted as the shadow of
absorption into inelastic channels. We here argue that the two formalisms are
just different views of the same phenomenon. We first demonstrate how this
relation works in a simple toy model, and then show how the relevant features
of the toy model are also realized in real perturbative QCD.
