Set Theoryhard
0:00.0

Let S={1,2,3}S = \{1, 2, 3\}. We define a 2×22 \times 2 matrix M=(ABABBAAB)M = \begin{pmatrix} |A \cap B| & |A \setminus B| \\ |B \setminus A| & |A \cup B| \end{pmatrix} where AA and BB are subsets of SS. How many different matrices MM can be formed as AA and BB vary over all possible subsets of SS?