Functionalist systems theories. The theorists in this tradition explain the emergence and/or maintenance of parts, structures, institutions, norms or… - Tom R. Burns

The rule systems governing transactions among agents in a defined sphere specify, to a greater or lesser extent, who participates (and who is excluded), who does what, when, where and how, and in relation to whom. ln particular, they define possible rights and obligations, including rules of command and obedience, governing specified categories of actors or roles vis a vis one another. The theory deals with the properties of social rule systems, their role in patterning social life, and the social and political processes whereby such systems are produced, maintained, and transformed as well as implemented in social action and interaction.

System theories have been applied to a wide spectrum of empirical cases and policy issues. Parsons and his followers, in particular, applied their systems theory to diverse empirical phenomena in sociology as well as in other disciplines: modernization, economics, politics, social order, industrialization and development, Fascism and McCarthyism, international relations, social change and evolution, complex organizations, health care, universities, religion, professions, small groups, and family as well as abstract questions such as the place of norms in maintaining social order both historically and cross-nationally. Marxian theory and dynamic system theories have also been applied to a spectrum of diverse empirical and policy subjects.

# Strategic structuring, informal or formal, whereby social agents, including the state, establish a rule regime regulating market access and transactions...