Refinement is a generic term of computer science that encompasses various approaches for producing correct computer programs and simplifying existing programs to enable their formal verification.
The progressive just-in-time preparation of the product backlog (requirements list) in agile software development approaches, such as Scrum, is also commonly described as refinement.
This reduces any nondeterminism in the specification, typically to a completely deterministic implementation.
However, we must be careful not to refine to x ∈ {} (equivalent to false) since this is unimplementable; it is impossible to select a member from the empty set.
The B-Method is also a formal method that extends refinement calculus with a component language: it has been used in industrial developments.