Aggregation and segregation

In this chapter a variety of models that produce aggregated patterns are considered. The common thread is that a simple process operating locally scales up in each case to produce clustered aggregate outcomes that are often intricately structured. Processes considered include local-averaging, various cellular automata processes, contact processes, and succession models. The well-known Schelling model of residential segregation provides another example. To some extent all of these are instances of an underlying reaction-diffusion process. An alternative to these bottom-up models, is a top-down subdivision or Voronoi process.