Union
$$A \cup B =$$
{ afraid, angry, confrontation, disgusted, happy, resolution, sad, setup, surprised }
Symmetric Difference
$$A \ominus B =$$
{ afraid, angry, confrontation, disgusted, happy, resolution, sad, setup, surprised }
Difference
$$A - B =$$
{ afraid, angry, disgusted, happy, sad, surprised }
Cartesian Product
$$A \times B =$$
{ (afraid, confrontation),
(afraid, resolution),
(afraid, setup),
(angry, confrontation),
(angry, resolution),
(angry, setup),
(disgusted, confrontation),
(disgusted, resolution),
(disgusted, setup),
(happy, confrontation),
(happy, resolution),
(happy, setup),
(sad, confrontation),
(sad, resolution),
(sad, setup),
(surprised, confrontation),
(surprised, resolution),
(surprised, setup) }
Paul Ekman