| public Set() | constructs an empty Set |
| public int cardinality() | Number of elements in this Set |
| public void insert(Comparable c) | Insert c into this Set |
| public void union(Set s) | Assign this = (this union s) |
| public void intersect(Set s) | Assign this = (this intersect s) |
| public String toString() | Express this Set as a String |