What we have sketched here is just a brief look at the possibilities
available in CLP programming systems: most of them offer a whole gamut
of primitive predicates and operations, which implement useful goodies
and specialized complex constraints found to be interesting in
practical cases. In particular, as an example, *Prolog IV* has also:

- Complementary intervals, which implement the exclusion of an interval.
- Boolean operations and constraints on them.
- Extended real operations, such as trigonometric operations, logarithms and other transcendental operations.
- Constraints on lists (about which we will see an example later).
- Constraints on integers, which force interval variables to take only integer values (or to exclude them), thus allowing the interval solver to be used with problems modeled using finite domains.

1998-12-03