Dijkstra's guarded-command language GCL contains explicit 'demonic' nondeterminism, representing abstraction from (or ignorance of ) which of two program fragments will be executed. We introduce probabilistic nondeterminism ...

The notion of a problem frame is introduced and explained, and its use in analysing and structuring problems is illustrated. A problem frame characterises a class of simple problem. Realistic problems are seen as compositions ...

In this paper we show how details of a software design emerges in two steps: software architecture and program organisation and from first having established careful descriptions of the application domain and of functional ...