Ontologies have gained popularity in the AI communityas a means for establishing explicit formal vocabulary to share between applications. Therefore,one can say that one of the goals of using ontologies is not to have the problem of heterogeneit yat all. It is of course unrealistic to hopethat there will be anagreementon on eorevena small set of ontologies. While having some common ground either within an application area or for some high-level general concepts could alleviatethe problemofsemanticheterogeneity,we will still need to map between ontologies, whether they extend the same top-level ontologyor are developedindependently.