On Fri, 29 Jul 2011, Conal Elliott wrote: > Is there a collection of laws associated with the Foldable class? Or for Traversable? - Conal Recently I asked the same question: http://www.haskell.org/pipermail/libraries/2011-June/016429.html and got the answer: http://www.cs.ox.ac.uk/jeremy.gibbons/publications/iterator.pdf