  A new approach to the construction of general persistent polyhierarchical
classifications is proposed. It is based on implicit description of category
polyhierarchy by a generating polyhierarchy of classification criteria.
Similarly to existing approaches, the classification categories are defined by
logical functions encoded by attributive expressions. However, the generating
hierarchy explicitly predefines domains of criteria applicability, and the
semantics of relations between categories is invariant to changes in the
universe composition, extending variety of criteria, and increasing their
cardinalities. The generating polyhierarchy is an independent, compact,
portable, and re-usable information structure serving as a template
classification. It can be associated with one or more particular sets of
objects, included in more general classifications as a standard component, or
used as a prototype for more comprehensive classifications. The approach
dramatically simplifies development and unplanned modifications of persistent
hierarchical classifications compared with tree, DAG, and faceted schemes. It
can be efficiently implemented in common DBMS, while considerably reducing
amount of computer resources required for storage, maintenance, and use of
complex polyhierarchies.
