 However, though it is impossible to anticipate "every" concept that a user may wish to represent in a computer, there is the possibility of finding some finite set of "primitive" concept representations that can be combined to create any of the more specific concepts that users may need for any given set of applications or ontologies.Having a foundation ontology (also called "upper ontology") that contains all those primitive elements would provide a sound basis for general semantic interoperability, and allow users to define any new terms they need by using the basic inventory of ontology elements, and still have those newly defined terms properly interpreted by any other computer system that can interpret the basic foundation ontology.Whether the number of such primitive concept representations is in fact finite, or will expand indefinitely, is a question under active investigation.