Union
$$A \cup B =$$
{ development, disease, earthquake, fire, flood, hurricane, introduction, lightning, meteor, resolution, reversal, volcano }
Symmetric Difference
$$A \ominus B =$$
{ development, disease, earthquake, fire, flood, hurricane, introduction, lightning, meteor, resolution, reversal, volcano }
Difference
$$B - A =$$
{ disease, earthquake, fire, flood, hurricane, lightning, meteor, volcano }
Cartesian Product
$$A \times B =$$
{ (development, disease),
(development, earthquake),
(development, fire),
(development, flood),
(development, hurricane),
(development, lightning),
(development, meteor),
(development, volcano),
(introduction, disease),
(introduction, earthquake),
(introduction, fire),
(introduction, flood),
(introduction, hurricane),
(introduction, lightning),
(introduction, meteor),
(introduction, volcano),
(resolution, disease),
(resolution, earthquake),
(resolution, fire),
(resolution, flood),
(resolution, hurricane),
(resolution, lightning),
(resolution, meteor),
(resolution, volcano),
(reversal, disease),
(reversal, earthquake),
(reversal, fire),
(reversal, flood),
(reversal, hurricane),
(reversal, lightning),
(reversal, meteor),
(reversal, volcano) }
KishÅtenketsu