Top-down design and stepwise refinement
urged the programmer to set forth the broad outlines of a procedure first and only later fill in the details.
Programming by stepwise refinement [Wirth 1973] is an example of such a process, albeit a somewhat informal one because the terms of the language are written partly in informal pseudocode.
Unlike stepwise refinement, we have in mind a fully formal mathematical system in which each refinement is formally provable by deduction from given axioms.
Third, as shown in  and , semiformal specifications can guide the stepwise refinement of formal specifications.
Alternatively, in cases where the problem domain is either ill defined or ill structured, and therefore, the requirements are yet to be discovered, a transitional-parallel stepwise refinement strategy would be appropriate.
The following common software design models that have been helpful in developing CAI models are briefly reviewed: composite or structural design model, Jackson model, META stepwise refinement
model, and higher-order software model.
A theoretical basis for stepwise refinement
and the programming calculus.
THE PARTIAL METRICS SYSTEM: MODELING THE STEPWISE REFINEMENT
PROCESS USING PARTIAL METRICS The Partial Metrics Sytem is designed to support the metrics-driven implementation of individual modules in a large-scale programming project [18-20].
In some ways knowledge abstration is most akin to earlier work on stepwise refinement
and program verification, which can be traced originally to Dijkstra .
Formal Models of Stepwise Refinement
of Programs Ali Mili, Jules Desharnais and Jean Raymond Gagne