Set Expressions

## 5.4 Set Expressions

In most positions where a set or set variable is expected one can also use a set expression. A set expression is composed from ground sets (integer lists), set variables, and the following set operators:

        Set1 /\ Set2       % intersection
        Set1 \/ Set2       % union
        Set1 \ Set2        % difference

When such set expressions occur, they are translated into auxiliary intersection/3, union/3 and difference/3 constraints, respectively.