Union
$$A \cup B =$$
{ ego, id, lucid, nightmare, ordinary, premonitory, superego, telepathic }
Symmetric Difference
$$A \ominus B =$$
{ ego, id, lucid, nightmare, ordinary, premonitory, superego, telepathic }
Difference
$$B - A =$$
{ lucid, nightmare, ordinary, premonitory, telepathic }
Cartesian Product
$$A \times B =$$
{ (ego, lucid),
(ego, nightmare),
(ego, ordinary),
(ego, premonitory),
(ego, telepathic),
(id, lucid),
(id, nightmare),
(id, ordinary),
(id, premonitory),
(id, telepathic),
(superego, lucid),
(superego, nightmare),
(superego, ordinary),
(superego, premonitory),
(superego, telepathic) }