Generating functions for aggregation and fragmentation: review

Abstract

In this work, we review and revisit the generating function techniques that provide exact analytical solutions for aggregation and fragmentation equations across several physical regimes including spontaneous and collisonal shattering. For discrete coagulation-fragmentation equations with size-independent rates under monodisperse initial conditions, we show the derivation of sevaral explicit closed-form solutions. We also briefly report the exact solutions for continuous, three-particle, $D$-particle collisions and two-component generalizations. Source-driven aggregation yields steady distributions featuring a universal $s^{-3/2}$ power-law decay and a cutoff mass scaling $s_{*} \sim t^{2}$.