That is, non-key attributes are functionally dependent on the superkey.
Tuples in a relation are by definition unique, with duplicates removed after each operation, so the set of all attributes is always uniquely valued for every tuple.
{employeeID} is a candidate key, since no subset of its attributes is also a superkey.
If attribute set K is a superkey of relation R, then at all times it is the case that the projection of R over K has the same cardinality as R itself.
For example, {Monarch Name, Royal House} cannot be a superkey because for the same attribute values (Edward, Plantagenet), there are two distinct tuples: Finally, after elimination, the remaining sets of attributes are the only possible superkeys in this example: In reality, superkeys cannot be determined simply by examining one set of tuples in a relation.