Union
$$A \cup B =$$
{ analyst, choleric, hysteric, master, melancholic, phlegmatic, sanguine, university }
Symmetric Difference
$$A \ominus B =$$
{ analyst, choleric, hysteric, master, melancholic, phlegmatic, sanguine, university }
Difference
$$A - B =$$
{ choleric, melancholic, phlegmatic, sanguine }
Difference
$$B - A =$$
{ analyst, hysteric, master, university }
Cartesian Product
$$A \times B =$$
{ (choleric, analyst),
(choleric, hysteric),
(choleric, master),
(choleric, university),
(melancholic, analyst),
(melancholic, hysteric),
(melancholic, master),
(melancholic, university),
(phlegmatic, analyst),
(phlegmatic, hysteric),
(phlegmatic, master),
(phlegmatic, university),
(sanguine, analyst),
(sanguine, hysteric),
(sanguine, master),
(sanguine, university) }
Four discourses