Bird–Meertens formalism

The Bird–Meertens formalism, also known as the Bird-Meertens algebra or the functional programming algebra, is a framework for defining and reasoning about algorithms in a high-level, mathematical way. It was developed primarily by two computer scientists, Richard Bird and Lambert Meertens. This formalism is particularly associated with functional programming and emphasizes the use of high-level abstractions to express algorithms in a way that is both concise and amenable to transformation.