A Coalgebraic Semantics of Subtyping
Department of Computer Science, University of Nijmegen,
P.O. Box 9010, 6500 GL Nijmegen, The Netherlands.
Accepted: 9 March 2001
Coalgebras have been proposed as formal basis for the semantics of objects in the sense of object-oriented programming. This paper shows that this semantics provides a smooth interpretation for subtyping, a central notion in object-oriented programming. We show that different characterisations of behavioural subtyping found in the literature can conveniently be expressed in coalgebraic terms. We also investigate the subtle difference between behavioural subtyping and refinement.
Mathematics Subject Classification: 18C50 / 68Q70 / 68Q85
© EDP Sciences, 2001