// A collection that contains no duplicate elements
public interface Set<E> extends Collection<E> {
	// Technically has no new methods from Collections
	// Java still has the Set interface and "redefines" the method headers
	// in this interface to provide more specific documentation and specification
	// for Set-like operations. Example:

	// Adds the given value to this set. Returns true if value
	// was distinct from all other values in the set (therefore was added successfuly)
	// and returns false if value is a duplicate with any value in the set currently.
	public boolean add(E value);
}