- ?Var in +Domain
- Var is an element of Domain. Domain is one of:
- Integer
- Singleton set consisting only of Integer.
- Lower .. Upper
- All integers I such that Lower =< I =< Upper.
Lower must be an integer or the atom inf, which
denotes negative infinity. Upper must be an integer or
the atom sup, which denotes positive infinity.
- Domain1 \/ Domain2
- The union of Domain1 and Domain2.