complementUnion<T> static method
Verifies the Complement Law for Union.
Law: A ∪ A' = U
The union of a set and its complement equals the universal set.
Implementation
static bool complementUnion<T>(CustomSet<T> a, CustomSet<T> universal) {
final complement = SetOperations.complement(a, universal);
return SetOperations.union(a, complement).equals(universal);
}