Property roles

Within a terminology model, properties my play different roles:

• Object type properties- Properties for known for each object instance of a given object type

• Fixed characteristics - Properties, which fixed values in specialized object types
• Optional properties - Properties, which might be associated with any object type

Object type properties and fixed characteristics are defined as properties of object types. Optional properties are defined as properties of a terminology model.

Object type properties describe a static view to an object, i.e. they describe relevant information to be provided for an object instance of the given object type (e.g. name, given names, birth date for object type person). Each object instance of a given object type provides property instances for the defined properties.

When one or more generalizations have been defined for an object type, fixed characteristics are a mean for defining specialized object types. E.g. the object type woman with a generalization person may define a fixed characteristics sex, which gets the value female for all object instances of object type woman. In this case, the fixed characteristics sex for woman will redefine the characteristics sex as being defined for object type person.

Optional properties are properties defined in the context of a terminology model, which may be associated with any object type defined in the terminology model and its subsequent models. Optional properties may be added to any type of object instance, but need not. Typical optional properties are remarks or notes, which do not really belong to any specific object type.