Union
$$A \cup B =$$
{ charismatic, concrete example, duel coding, elaboration, interleaving, legal, retrieval, spaced practice, traditional }
Symmetric Difference
$$A \ominus B =$$
{ charismatic, concrete example, duel coding, elaboration, interleaving, legal, retrieval, spaced practice, traditional }
Difference
$$A - B =$$
{ concrete example, duel coding, elaboration, interleaving, retrieval, spaced practice }
Cartesian Product
$$A \times B =$$
{ (concrete example, charismatic),
(concrete example, legal),
(concrete example, traditional),
(duel coding, charismatic),
(duel coding, legal),
(duel coding, traditional),
(elaboration, charismatic),
(elaboration, legal),
(elaboration, traditional),
(interleaving, charismatic),
(interleaving, legal),
(interleaving, traditional),
(retrieval, charismatic),
(retrieval, legal),
(retrieval, traditional),
(spaced practice, charismatic),
(spaced practice, legal),
(spaced practice, traditional) }