deletions | additions       diff --git a/Sternheimer.tex b/Sternheimer.tex  index 3c99681..794e6aa 100644  --- a/Sternheimer.tex  +++ b/Sternheimer.tex 
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\Big\}\ ,  \end{equation}  %\end{multline}  needs to be calculated self-consistently. The first order variation of the Kohn-Sham KS  Hamiltonian is %\begin{multline}  \begin{equation} \begin{multline}  \label{eq:h1}  \delta{H}(\omega)=  \delta{V}(\vec{r}) \delta{\hat H}(\omega)=  \delta{v}(\vec{r})  +\int \mathrm{d}\vec{r}' \frac{\delta{n}(\vec{r}',\omega)}{|\vec{r}-\vec{r}'|} \frac{\delta{n}(\vec{r}',\omega)}{|\vec{r}-\vec{r}'|}\\  +\int \mathrm{d}\vec{r}' f_{\rm xc}(\vec r, \vec r', \omega)\,\delta{n}(\vec{r'}, \omega)  \ ,  \end{equation} \end{multline}  %  \(\mathrm{P}_c\) is a projector operator, and  \(\eta\) a positive in\-fi\-ni\-te\-si\-mal, essential to obtain the