Outputs (2)

The Generic Approximation Lemma (2001)
Journal Article
Hutton, G., & Gibbons, J. (2001). The Generic Approximation Lemma. Information Processing Letters, 79(4), https://doi.org/10.1016/S0020-0190%2800%2900220-9

The approximation lemma is a simplification of the well-known take lemma, and is used to prove properties of programs that produce lists of values. We show how the approximation lemma, unlike the take lemma, can naturally be generalised from lists t... Read More about The Generic Approximation Lemma.

When is a function a fold or an unfold? (2001)
Presentation / Conference Contribution
Gibbons, J., Hutton, G., & Altenkirch, T. When is a function a fold or an unfold?. Presented at Workshop on Coalgebraic Methods in Computer Science (4th)

We give a necessary and sufficient condition for when a set-theoretic function can be written using the recursion operator fold, and a dual condition for the recursion operator unfold. The conditions are simple, practically useful, and generic in the... Read More about When is a function a fold or an unfold?.