On Mar 31, 2006, at 2:22 PM, yoann padioleau wrote:
> If you can represent the y by integers, and that the binary relation
> have good property, such as the set of y related to a x (the extension 
> of x in concept analysis ?) often follows each other,  then you can 
> represent sets  by  list of intervals.

Indeed, this is related to Concept Analysis. My old implementation is 
in C

	http://www.st.cs.uni-sb.de/~lindig/src/concepts.html

and I'd like to have a better structured implementation in Caml. I 
don't care for the last bits of performance.

-- C