Behavioural Subtyping Relations for Object-Oriented Formalisms

  • Clemens Fischer
  • Heike Wehrheim
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1816)


In this paper we investigate the object-oriented notion of subtyping in the context of behavioural formalisms. Subtyping in OO-formalisms is closely related to the concept of inheritance. The central issue in the choice of subtyping relations among classes is the principle of substitutability: an instance of the subtype should be usable wherever an instance of the supertype was expected. Depending on the interpretation of “usable”, we obtain a variety of subtyping relations: stronger subtyping relations, allowing one to share the subtype instance among different clients without any change compared with the supertype, and weaker relations, restricting the possibilities of interference of different clients on the subtype instance. The subtyping relations are taxonomically ordered in a hierarchy. The concept of “usability” is formalised via testing scenarios, which provide alternative characterisations for the subtyping relations.


Transition System Testing Scenario Parallel Composition Label Transition System Process Algebra 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Clemens Fischer
    • 1
  • Heike Wehrheim
    • 1
  1. 1.Fachbereich InformatikUniversität OldenburgOldenburgGermany

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