Co-evolution as the secret of urban complexity

I choose to enter through an object ‚Ä"system of cities- and a discipline ‚Ä"geography-to sift through cross-formalizations to complex urban systems. The objective is to identify what are the specificities of the organization and evolution of these social systems observed in their spatial, planetary and global dimension. Backed by a long historiographic tradition comparative research enables to develop a spiral perspective of the cumulativeness of knowledge. Statistical analysis of urban growth generated the first explanatory models of the surprising persistency of urban hierarchies. The concept of urban co-evolution emerged as an evidence when enlarging investigations toward the diffusion of socio-economic changes in national urban systems. Mathematical modeling and simulations with multi-agents systems validate explanatory principles in an evolutionary theory of urban systems. Generic processes of urban interactions combine with a variety of territorialized political, demographic, environmental, economic or cultural processes, informing thinking about the future of cities and their diversity.