The article discusses the ways of creating unified economic theory describing the functioning and interaction of significant units of the national economy and the economy as a whole. The general construction of a unified economic theory, its connection with the system economic theory and its system components (object, process, project, environmental economic theories) is determined. Based on the example of institutional economic theory, it is shown that the expansion of its terminology and conceptual apparatus within the framework of the construction of a unified multi-level economic theory allows minimizing the contradictions between the “old” and “new” institutionalism, methodological individualism and methodological holism. This expansion is carried out following the principle of the maximum possible system community in two lines. The first line is expanding the subject area (along with organizations as systems of the object type, systems of the process, project, the environment types are also considered as the focal subject of study). The second line is the expanding the instrumental area (analysis of the influence on the behavior of agents from not only institutional subsystems but also information, infrastructural, network, mental, and other environmental subsystems). As a result, each system receives the compact and maximum volumetric internal systemic content and, at the same time, the minimum volumetric external systemic environment, which creates conditions for the effective application of the duality principle in the theory of economic systems. Thus, the system expansion of institutional theory should take place in two lines: content of the theory per se and creation of its immediate environment.
On the subject reduction property for algebraic type systems
