Hierarchy Theory

Hierarchy theory is a system theory about the structure, function, and dynamics of complex systems. A hierarchy is an ordered system of several units, whilst complexity often has a hierarchical form. A complex system often consists of some interrelated subsystems, which also include respective subsystems, and so on, down to the lowest level.?Therefore, each level in the hierarchical system is composed of different subsystems or elements, and each level of the unit shows the whole characteristics relative to the lower level, and shows a dependency or constraint towards the higher level. Based on the hierarchy theory, complex system can be regarded as a hierarchical system consisting of discrete hierarchies. 

Edited and translated by Zhang Yifei