  Topological effects produce chaos in multiagent simulation and distributed
computation. We explain this result by developing three themes concerning
complex systems in the natural and social sciences: (i) Pragmatically, a system
is complex when it is represented efficiently by different models at different
scales. (ii) Nontrivial topology, identifiable as we scale towards the global,
induces complexity in this sense. (iii) Complex systems with nontrivial
topology are typically chaotic.
