In aggregation, reactive clusters join irreversibly whenever two of them meet. Aggregation is ubiquitous in Nature: it underlies milk curdling, blood coagulation, and star formation by gravitational accretion. Aggregation also beautifully illustrates some paradigmatic features of non-equilibrium phenomena, such as scaling, phase transitions, and non-trivial steady states. Here we describe these generic features and present exact solutions of a few tractable models of aggregation.
5.1 The master equations
In kinetic theory, which ...