Abstract: A class description is used to represent the concept in OWL DL (Description Logic). Collection operation in theory can lead to arbitrarily complex concept. The current collection operation of OWL DL can be achieved with intersection,union and complement,and OWL can not represent set expression with a number of constraints. This paper extended the cardinality constraint on the basis of OWL DL set limit,which can achieve the description logic with number of set constraints. And we proposed a tree classify reasoning algorithm based on collection cardinality.The application of human resources screening proves that this method is flexible in expression and very effective in individual classification.

Key words: Ontology,OWL,Description logic,Cardinality constraint,Reasoning