Adjoint eigenvector identity for a normal matrix ($Ax=lambdaxRightarrow{A}^{d}aggerx=overlinelambdax$)

If a normal matrix satisfies $Ax=\lambda x$, then $A^{†}x=\overline{\lambda }x$. Indeed, $M=A-\lambda I$ is normal and $\Vert Mx{\Vert }^2=x^{†}{M}^{†}Mx=x^{†}M{M}^{†}x=\Vert M^{†}x{\Vert }^2$. Since $Mx=0$, also $M^{†}x=0$. This identity proves orthogonality of distinct eigenspaces and gives spectral restrictions for Hermitian matrices, skew-Hermitian matrices and unitary matrices.