\[\left\langle\left(z-T\right)^{-1}f,f\right\rangle=\sum_{\boldsymbol{\sigma}_{p%
}}\frac{{\left|\widehat{f}(\lambda_{n})\right|}^{2}}{z-\lambda_{n}}+\int_{%
\boldsymbol{\sigma}_{c}}{\left|\widehat{f}(\lambda)\right|}^{2}\frac{\,\mathrm%
{d}\lambda}{z-\lambda},\]