Union
$$A \cup B =$$
{ Electromagnetic Force., Gravity., Strong Force., Weak Force., gas, liquid, plasma, solid }
Symmetric Difference
$$A \ominus B =$$
{ Electromagnetic Force., Gravity., Strong Force., Weak Force., gas, liquid, plasma, solid }
Difference
$$A - B =$$
{ Electromagnetic Force., Gravity., Strong Force., Weak Force. }
Difference
$$B - A =$$
{ gas, liquid, plasma, solid }
Cartesian Product
$$A \times B =$$
{ (Electromagnetic Force., gas),
(Electromagnetic Force., liquid),
(Electromagnetic Force., plasma),
(Electromagnetic Force., solid),
(Gravity., gas),
(Gravity., liquid),
(Gravity., plasma),
(Gravity., solid),
(Strong Force., gas),
(Strong Force., liquid),
(Strong Force., plasma),
(Strong Force., solid),
(Weak Force., gas),
(Weak Force., liquid),
(Weak Force., plasma),
(Weak Force., solid) }