“…Let us mention here that the original model proposed by Smoluchowski was introduced to analyze the binary coagulation of colloids moving according to brownian motions and several additional physical processes have been subsequently incorporated into the model (fragmentation, condensation, influence of external fields, see, e.g., [10]). The field of applications of the Smoluchowski model has meanwhile widened and now includes, among others, aerosol science (evolution of a system of solid or liquid particles suspended in a gas [10,19]), astrophysics (formation of the planets [18]), polymer science and hematology (red blood cell aggregation [17]). We refer to [10] for derivations of the model, together with some physical background.…”