finite set select intersection

[Guido Tack]

Hi.

Irene Langkilde Geary wrote:
> What I really am wishing for is a set partition propagator like
> {Select.partition $MVs $M1 $M2}, where M1 selects elements from MVs that 
> partition M2, but none of the sets are predetermined.  The Select.union 
> gives me half of what I want.  A Select.disjoint on MVs and M1 would 
> give me the other half, if it existed.
> 

I tried to implement that propagator a while ago, but I couldn't come up 
with propagation rules that looked complete. I am sure now that a 
complete propagation algorithm is NP hard as soon as you want to take 
cardinality information into account - and for our application, 
propagation without cardinality turned out to be too weak.

 > Any suggestions on how to accomplish this with the propagators already
 > available?  I'm not yet to the point where I think I could write it
 > myself in C++ (nor do I have the time for that right now) but I do
 > have an immediate need for it.

At the moment, I can't think of any way to break this down into more 
basic constraints.

Guido