When is a function a fold or an unfold?

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 underlying datatype.

Bibliographic Details
Main Authors: Gibbons, Jeremy, Hutton, Graham, Altenkirch, Thorsten
Format: Conference or Workshop Item
Published: Elsevier Science 2001
Online Access:https://eprints.nottingham.ac.uk/28196/
_version_ 1848793522709200896
author Gibbons, Jeremy
Hutton, Graham
Altenkirch, Thorsten
author_facet Gibbons, Jeremy
Hutton, Graham
Altenkirch, Thorsten
author_sort Gibbons, Jeremy
building Nottingham Research Data Repository
collection Online Access
description 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 underlying datatype.
first_indexed 2025-11-14T19:01:38Z
format Conference or Workshop Item
id nottingham-28196
institution University of Nottingham Malaysia Campus
institution_category Local University
last_indexed 2025-11-14T19:01:38Z
publishDate 2001
publisher Elsevier Science
recordtype eprints
repository_type Digital Repository
spelling nottingham-281962020-05-04T20:32:33Z https://eprints.nottingham.ac.uk/28196/ When is a function a fold or an unfold? Gibbons, Jeremy Hutton, Graham Altenkirch, Thorsten 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 underlying datatype. Elsevier Science 2001-05 Conference or Workshop Item PeerReviewed Gibbons, Jeremy, Hutton, Graham and Altenkirch, Thorsten (2001) When is a function a fold or an unfold? In: Workshop on Coalgebraic Methods in Computer Science (4th), 6-7 April 2001, Genova, Italy. http://www.sciencedirect.com/science/article/pii/S157106610480906X
spellingShingle Gibbons, Jeremy
Hutton, Graham
Altenkirch, Thorsten
When is a function a fold or an unfold?
title When is a function a fold or an unfold?
title_full When is a function a fold or an unfold?
title_fullStr When is a function a fold or an unfold?
title_full_unstemmed When is a function a fold or an unfold?
title_short When is a function a fold or an unfold?
title_sort when is a function a fold or an unfold?
url https://eprints.nottingham.ac.uk/28196/
https://eprints.nottingham.ac.uk/28196/