What is a system?

Abstract

A new definition and model of a system is presented utilizing graph theoretic concepts and introducing nested graphs. By a comprehensive search of the literature, this abstract formulation of a system is shown to incorporate extant theory. The approach of Emery and Trist using open and closed systems, the system-environment model of Cartwright and Harary, and the structural role system of Oeser and Harary are all subsumed as special cases. The value of such a theory is discussed in statistical terms by considering correlational problems and Simpson's paradox. A general problem-solving algorithm is presented, using this model of a system, suggested by a simultaneous generalization of the statistical procedures of cluster analysis and stagewise regression. An example is interpreted in the nested network framework, illustrating the applicability of the model to empirical situations.