Factorization of discontinuities of multi-Regge amplitudes

It is shown that an arbitrary discontinuity of an arbitrary multi- Regge amplitude factorizes in a large class of models which encompasses the dual resonance model. It is argued that multiple discontinuities also factorize and that the factorization of discontinuities is expected to hold on very general grounds as a result of the singularity structure of multiparticle amplitudes. These results allow the full amplitude as well as its discontinuities to be written as a product of Regge propagators, single-, double- and triple-Regge vertices and their discontinuities. (24 refs).