Solution
= Solution
All three Pauli <matrices> are Hermitian. Direct multiplication gives $\sigma_a^2=I$ and, for $a\ne b$, $\sigma_a\sigma_b=i\varepsilon_{abc}\sigma_c$, which combines as the displayed identity.
= Solution
All three Pauli <matrices> are Hermitian. Direct multiplication gives $\sigma_a^2=I$ and, for $a\ne b$, $\sigma_a\sigma_b=i\varepsilon_{abc}\sigma_c$, which combines as the displayed identity.