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

On Sat, Nov 14, 2009 at 9:21 AM, Mark Wassell 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