Themes and citation order in free classification

Abstract

Free classification consists of combining notation for several concepts without specifying the relationships between them. Some properties of free classification are described and discussed. The citation order of concepts can either follow a conventional rule, or express the differential relevance of base theme, subordinate themes, and possibly rheme dealt with in the indexed knowledge source. Citing base theme first allows for a more helpful collocation of the record close to others having a similar base theme. Examples are illustrated from the Mathematics Subject Classification, the Knowledge Organization Literature Classification, and the Integrative Levels Classification. Finally, the problem of identifying themes of fictional works is briefly discussed.