  A generalization of the addition relation for the Riemann theta functions and
its limiting version for exponential functions appearing in soliton type
equations are reported. The presented form seems to be particularly useful when
processes in N+1, (N>1) space-time are analyzed. The commonly applied bilinear
and trilinear approaches, restricted to the pure soliton processes, represent
particular cases of the reported formalism. As an example, the dispersion
equation for either quasiperiodic or soliton processes following 2+1
Calogero-Bogoyavlenskij-Schiff equation is derived.
