Union
$$A \cup B =$$
{ accumulating, friend, handmaid, master, praiseworthy, reformulating, sister, trans-framing, undesirable, uni-framing, wasteful }
Symmetric Difference
$$A \ominus B =$$
{ accumulating, friend, handmaid, master, praiseworthy, reformulating, sister, trans-framing, undesirable, uni-framing, wasteful }
Difference
$$A - B =$$
{ friend, handmaid, master, praiseworthy, sister, undesirable, wasteful }
Cartesian Product
$$A \times B =$$
{ (friend, accumulating),
(friend, reformulating),
(friend, trans-framing),
(friend, uni-framing),
(handmaid, accumulating),
(handmaid, reformulating),
(handmaid, trans-framing),
(handmaid, uni-framing),
(master, accumulating),
(master, reformulating),
(master, trans-framing),
(master, uni-framing),
(praiseworthy, accumulating),
(praiseworthy, reformulating),
(praiseworthy, trans-framing),
(praiseworthy, uni-framing),
(sister, accumulating),
(sister, reformulating),
(sister, trans-framing),
(sister, uni-framing),
(undesirable, accumulating),
(undesirable, reformulating),
(undesirable, trans-framing),
(undesirable, uni-framing),
(wasteful, accumulating),
(wasteful, reformulating),
(wasteful, trans-framing),
(wasteful, uni-framing) }
Marvin Minsky