- class: identified by numbers preceded by the letter "E"
- subclass: specialization of another class (its superclass)
- superclass: generalization of one or more other classes (its subclasses)
- multiple inheritance: a class may have more than one immediate superclass
- property: identified by numbers preceded by the letter "P" (define relationship between two classes)
- subproperty: specialization of another property (its superproperty)
- superproperty: a generalization of one or more other properties (its subpropperties)
- intension (of a class or property): its intended meaning
- extension (of a class): the set of real life instances
belonging to the class that fulfil the criteria of its intension (with the "Open World Assumption")
- Open World Assumption: information stored is incomplete relative to the
universe of discourse they intend to describe
Properties can have properties, such as in the case of an Activity (E7)
carried out (P14) by an Actor (E39).
- Example: the painting of the Sistine Chapel (E7) was carried out by (P14.1) Michelangelo Buonarroti (E21)
in the role of master craftsman (E55)
- (Note that E21 Person is a subclass of E39 Actor)
