Denotational descriptions are frequently presented in terms of a sequence of descriptions of programming languages of increasing complexity. We discuss a formal approach to the study of such description sequences in terms of a refinement relation, showing how the informal use made of this approach in tutorial introductions to denotational semantics may be formally justified.
Proceedings of the 1st Irish Workshop on Formal Methods,Dublin, Ireland, 3-4 July 1997 (to appear).