Coverage, invariability and orbits by structural functions

Purpose – Based on some of the results and definitions provided in the paper “system linkage: structural functions and hierarchies” and adding new definitions that are in keeping with the spirit of the same paper, new results have been obtained that explore the utility of the structural input‐output function.Design/methodology/approach – Our approach is based principally on the application of graph theory to the study of relationships between variables using specific set theory concepts.Findings – A result such as the fact that A covers B, for example, can be interpreted in terms of the latter set being formed of direct influences from elements in the former set in relation to one or more than one relationships. Analogously, the invariant set concept may be interpreted as the set maintaining its structure and status, remaining constant with respect to any possible relationships.Originality/value – From a practical point of view, in the context of the study of networks within an ecosystem, authors (such as...