Union
$$A \cup B =$$
{ adenine, cytosine, ethos, guanine, kairos, logos, pathos, thymine }
Symmetric Difference
$$A \ominus B =$$
{ adenine, cytosine, ethos, guanine, kairos, logos, pathos, thymine }
Difference
$$A - B =$$
{ adenine, cytosine, guanine, thymine }
Difference
$$B - A =$$
{ ethos, kairos, logos, pathos }
Cartesian Product
$$A \times B =$$
{ (adenine, ethos),
(adenine, kairos),
(adenine, logos),
(adenine, pathos),
(cytosine, ethos),
(cytosine, kairos),
(cytosine, logos),
(cytosine, pathos),
(guanine, ethos),
(guanine, kairos),
(guanine, logos),
(guanine, pathos),
(thymine, ethos),
(thymine, kairos),
(thymine, logos),
(thymine, pathos) }