Re: [eclipse-clp-users] fd_sets sameset negation

Matthew Skala wrote:
> 
> When I ran into a similar situation, where I wanted a "neither of these
> sets is a subset of the other" constraint in ic_sets, I ended up
> adding a customized constraint like this:

This can also be expressed by combining other constraints, e.g.
set-difference and cardinality:

not_subsets(X, Y) :-
	#(X\Y) #>= 1,
	#(Y\X) #>= 1.


The overhead would be higher than with Matthew's passive checking,
but it produces propagation (which may or may not be worthwhile):

?- X in_set_range [1, 2] .. [1, 2, 3, 4],
   Y in_set_range [1, 2, 3] .. [1, 2, 3, 4],
   not_subsets(X, Y).
X = [1, 2, 4]
Y = [1, 2, 3]
Yes (0.00s cpu)


-- Joachim