Union
$$A \cup B =$$
{ Formal, Natural, Social, aquarius, aries, cancer, capricorn, gemini, leo, libra, pisces, sagittarius, scorpio, taurus, virgo }
Symmetric Difference
$$A \ominus B =$$
{ Formal, Natural, Social, aquarius, aries, cancer, capricorn, gemini, leo, libra, pisces, sagittarius, scorpio, taurus, virgo }
Difference
$$A - B =$$
{ aquarius, aries, cancer, capricorn, gemini, leo, libra, pisces, sagittarius, scorpio, taurus, virgo }
Cartesian Product
$$A \times B =$$
{ (aquarius, Formal),
(aquarius, Natural),
(aquarius, Social),
(aries, Formal),
(aries, Natural),
(aries, Social),
(cancer, Formal),
(cancer, Natural),
(cancer, Social),
(capricorn, Formal),
(capricorn, Natural),
(capricorn, Social),
(gemini, Formal),
(gemini, Natural),
(gemini, Social),
(leo, Formal),
(leo, Natural),
(leo, Social),
(libra, Formal),
(libra, Natural),
(libra, Social),
(pisces, Formal),
(pisces, Natural),
(pisces, Social),
(sagittarius, Formal),
(sagittarius, Natural),
(sagittarius, Social),
(scorpio, Formal),
(scorpio, Natural),
(scorpio, Social),
(taurus, Formal),
(taurus, Natural),
(taurus, Social),
(virgo, Formal),
(virgo, Natural),
(virgo, Social) }