Union
$$A \cup B =$$
{ activist, lucid, nightmare, ordinary, pragmatist, premonitory, reflector, telepathic, theorist }
Symmetric Difference
$$A \ominus B =$$
{ activist, lucid, nightmare, ordinary, pragmatist, premonitory, reflector, telepathic, theorist }
Difference
$$A - B =$$
{ lucid, nightmare, ordinary, premonitory, telepathic }
Difference
$$B - A =$$
{ activist, pragmatist, reflector, theorist }
Cartesian Product
$$A \times B =$$
{ (lucid, activist),
(lucid, pragmatist),
(lucid, reflector),
(lucid, theorist),
(nightmare, activist),
(nightmare, pragmatist),
(nightmare, reflector),
(nightmare, theorist),
(ordinary, activist),
(ordinary, pragmatist),
(ordinary, reflector),
(ordinary, theorist),
(premonitory, activist),
(premonitory, pragmatist),
(premonitory, reflector),
(premonitory, theorist),
(telepathic, activist),
(telepathic, pragmatist),
(telepathic, reflector),
(telepathic, theorist) }