Suppose I have a hermitian operator $\Omega$. The proof of the existence of a orthonormal eigenbasis as given in Shankar is given.
What I don't understand is why the second eigenvector $\left| \omega_2 \right> $ of matrix $\Omega$ belongs to the subspace $V^{n-1}_{\perp 1}$ orthogonal to the first eigenvector $\left| \omega_1 \right> $?