[Haskell-cafe] Collection of sets containing no sets which are a subset of another in the collection

[Max Rabkin]

On Sat, Nov 14, 2009 at 9:21 AM, Mark Wassell <mwassell at bigpond.net.au> wrote:
> Hi,
>
> I am looking for a data structure that will represent a collection of sets
> such that no element in the collection is a subset of another set. In other
> words, inserting an element that is already a subset of another element will
> return the original collection, and inserting an element that is a superset
> of any elements will result in a collection with the superset added and the
> subsets removed.

I *think* what you're describing is a Union-Find structure. A
functional union-find structure is described in
http://www.lri.fr/~filliatr/ftp/publis/puf-wml07.ps (the language used
is OCaml, but if you have any difficulty translating it to Haskell I'm
sure this list will offer its help).

--Max