A crucial component of a medical concept representation system is the class
ifier. It requires features that are not sufficiently supported by current
logic based formalisms like description logics and conceptual graphs. Those
features are, for instance, the representation of partitive and spatial re
lations and their impact on subsumption. This paper introduces graph orient
ed classification operators for a concept representation language with norm
al forms. Emphasis is on the separation of generic and partitive relations
and on the mutual interdependence of subsumption and part-whole. For that p
urpose operators are given for formal subsumption, formal part-whole, subsu
mptive part-whole and part-sensitive subsumption. These operators are based
on the formal structure of concept descriptions and on explicitly introduc
ed generic and partitive relationships between their constituents.