Subsumption principles underlying medical concept systems and their formal reconstruction.

Conventional medical concept systems represent generic concept relations by hierarchical coding principles. Often, these coding principles constrain the concept system and reduce the potential for automatical derivation of subsumption. Formal reconstruction of medical concept systems is an approach that bases on the conceptual representation of meanings and that allows for the application of formal criteria for subsumption. Those criteria must reflect intuitive principles of subordination which are underlying conventional medical concept systems. Particularly these are: The subordinate concept results (1) from adding a specializing criterion to the superordinate concept, (2) from refining the primary category, or a criterion of the superordinate concept, by a concept that is less general, (3) from adding a partitive criterion to a criterion of the superordinate, (4) from refining a criterion by a concept that is less comprehensive, and finally (5) from coordinating the superordinate concept, or one of its criteria. This paper introduces a formalism called BERNWARD that aims at the formal reconstruction of medical concept systems according to these intuitive principles. The automatical derivation of hierarchical relations is primarily supported by explicit generic and explicit partititive hierarchies of concepts, secondly, by two formal criteria that base on the structure of concept descriptions and explicit hierarchical relations between their elements, namely: formal subsumption and part-sensitive subsumption. Formal subsumption takes only generic relations into account, part-sensitive subsumption additionally regards partive relations between criteria. This approach seems to be flexible enough to cope with unforeseeable effects of partitive criteria on subsumption.