SUBSTRUCTURE SYSTEMS - CONCEPTS AND CLASSIFICATIONS

The duality of the notion of substructure—whole vs part, element vs class—leads to varying levels of abstraction, each associated with different aspects of the evolving models for representation. The concepts underlying substructure definitions are discussed and are related to the problems of representation. Substructures are often goal-oriented, emphasizing some typical feature. The main approaches to substructure systems are reviewed in the light of various classifications, allowing representation of the same entity from different standpoints. A generic model, an extension of the graph-specific structure, provides a basic model which unifies structure and substructure and yields a formal tool for representation and evaluation. © 1990, American Chemical Society. All rights reserved.