You can use the following three operations on process sets:
| Operation | Represents | Action |
|---|---|---|
| + | Set union | Takes two sets S1 and S2 and returns a set whose elements are either in S1 or in S2. |
| - | Difference | Takes two sets S1 and S2 and returns a set whose elements are in S1 but not in S2. |
| unary - | Negation | Takes a single set S and returns the difference of [*] and S. |
The following example demonstrates these operations:
(idb) set $set1 = [:10, 15:18, 20:]
(idb) set $set2 = [10:16, 19]
(idb) set $set3 = $set1 + $set2
(idb) print $set3
[*]
(idb) print $set3 - $set2
[:9, 17:18, 20:]
(idb) print -$set2
[:9, 17:18, 20:]