Abstract
In semantic and object-oriented data models, each class has one or more typing properties that associate it to other classes, and carry type information about all instances of the class. We introduce a new kind of property that we call instance-typing property. An instance-typing property associates an instance of a class to another class, and carries type information about that particular instance (and not about all instances of the class). Instance-typing properties are important as they allow to represent summary information about an instance, in addition to specific information. In this paper, we study inheritance of properties from a class to an instance, using type information about the class, as well as type information about the instance. This kind of inheritance, that we call contextual instance-inheritance, provides us with the most specific type information about the instance, in a particular context. Intuitively, a context is a metaclass of interest with respect to which this most specific information is determined. We demonstrate that contextual instance-inheritance is a powerful conceptual modeling mechanism, capable of expressing valuable information about instances. We also provide a framework in which derived instance-inherited properties can be represented and retrieved in the same way as ``usual'' properties.