Subsumption in partially ordered sets

[Tom Pledger]

Graham Klyne writes:
 :
 | Below is some code I have written, which works, but I'm not sure
 | that it's especially efficient or elegant.  Are there any published
 | Haskell libraries that contain something like this?

Hi.

Partially ordered sets are in cahoots with lattices, so you may be
interested in http://www.cse.ogi.edu/~mpj/pubs/lattices.html .

And here's some off-the-cuff feedback...

How about using Maybe Ordering, instead of a new data type?
(As in http://www.mail-archive.com/haskell@haskell.org/msg05635.html)

Instead of hard-wiring Maybe into the element type in dropSubsumed,
how about passing in a partial comparison function?

    dropSubsumedBy :: (a -> a -> Maybe Ordering) -> [a] -> [a]

- Tom