Express S 2 {\displaystyle {\frac {}{}}S^{2}} for two spin-1/2 particles in the direct product basis.
ℏ 2 ( 2 0 0 0 0 1 1 0 0 1 1 0 0 0 0 2 ) {\displaystyle {\hbar }^{2}{\begin{pmatrix}2&0&0&0\\0&1&1&0\\0&1&1&0\\0&0&0&2\\\end{pmatrix}}}
for two spin-1/2 particles in the direct product basis.
