The Theory of Classification, Part 8: Classification and Inheritance.
Anthony J. H. Simons · The Journal of Object Technology · 2003
The theory of classification in object oriented languages are discussed. The differences between classes and types in object oriented languages are described by developing the alternative formal model of classification and inheritance. Extensibility and polymorphism are the two characteristics that hold classes apart from the traditional variable types. Classes are used to refer to a polymorphic family and types are used to refer one member of this family.