Complex System - Overview

Overview

A complex system is a network of heterogeneous components that interact nonlinearly, to give rise to emergent behavior. The term complex systems has multiple meanings depending on its scope:

• A specific kind of systems which are complex
• A field of science studying these systems; see further complex systems
• A paradigm that complex systems have to be studied with non-linear dynamics; see further complexity

Various informal descriptions of complex systems have been put forward, and these may give some insight into their properties. A special edition of Science about complex systems highlighted several of these:

• A complex system is a highly structured system, which shows structure with variations (N. Goldenfeld and Kadanoff)
• A complex system is one whose evolution is very sensitive to initial conditions or to small perturbations, one in which the number of independent interacting components is large, or one in which there are multiple pathways by which the system can evolve (Whitesides and Ismagilov)
• A complex system is one that by design or function or both is difficult to understand and verify (Weng, Bhalla and Iyengar)
• A complex system is one in which there are multiple interactions between many different components (D. Rind)
• Complex systems are systems in process that constantly evolve and unfold over time (W. Brian Arthur).