$\newcommand{\+}{^{\daga}}
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\newcommand{\llaves}[1]{\left\lbrace\, nº 1 \,\right\rbrace}
\newcommand{\bracks}[1]{\left\lbrack\, nº 1 \,\right\rbrack}
\newcommand{\ceil}[1]{\,\left\lceil\, nº 1 \,\right\rceil\,}
\newcommand{\dd}{{\rm d}}
\newcommand{\down}{\downarrow}
\newcommand{\ds}[1]{\displaystyle{#1}}
\newcommand{\expo}[1]{\,{\rm e}^{#1}\,}
\newcommand{\fermi}{\,{\rm f}}
\newcommand{\piso}[1]{\,\left\lfloor #1 \right\rfloor\,}
\newcommand{\mitad}{{1 \over 2}}
\newcommand{\ic}{{\rm i}}
\newcommand{\iff}{\Longleftrightarrow}
\newcommand{\imp}{\Longrightarrow}
\newcommand{\isdiv}{\,\left.\a la derecha\vert\,}
\newcommand{\cy}[1]{\left\vert #1\right\rangle}
\newcommand{\ol}[1]{\overline{#1}}
\newcommand{\pars}[1]{\left (\, nº 1 \,\right)}
\newcommand{\partiald}[3][]{\frac{\partial^{#1} #2}{\parcial #3^{#1}}}
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\newcommand{\raíz}[2][]{\,\sqrt[#1]{\vphantom{\large Un}\,#2\,}\,}
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\newcommand{\totald}[3][]{\frac{{\rm d}^{#1} #2}{{\rm d} #3^{#1}}}
\newcommand{\ul}[1]{\underline{#1}}
\newcommand{\verts}[1]{\left\vert\, nº 1 \,\right\vert}
\newcommand{\wt}[1]{\widetilde{#1}}$
$\ds{}$
\begin{align}&\color{#66f}{\large{1 \over 2\pi\ic}\int_{\verts{z}\ =\ 1}{\ol{\fermi\pars{z}} \over z - a} \,\dd z}
=\ol{\vphantom{\Huge A^{a}}\bracks{-\,{1 \over 2\pi\ic}
\int_{\verts{\color{#c00000}{\LARGE\ol{z}}}\ =\ 1}
{\fermi\pars{z} \over \ol{z} - \ol{a}}\,\dd\ol{z}}}
\qquad\qquad\qquad\qquad\qquad\quad\pars{1}
\\[3mm]&=\ol{\vphantom{\Huge A^{a}}\bracks{-\,{1 \over 2\pi\ic}
\int_{\verts{z}\ =\ 1}{%
\fermi\pars{z} \over 1/z - \ol{a}}\,\pars{-\,{\dd z \over z^{2}}}}}
=\ol{\vphantom{\Huge A^{a}}\bracks{-\,{1 \over 2\pi\ic}
\int_{\verts{z}\ =\ 1}{%
\fermi\pars{z} \over \ol{a}z\pars{z - 1/\ol{a}}}\,\dd z}}\qquad\quad\pars{2}
\\[3mm]&=\left\lbrace\begin{array}{rclcl}
\ol{\left.-\,{1 \over 2\pi\ic}\,2\pi\ic\,
{\fermi\pars{z} \over \ol{a}\pars{z - 1/\ol{a}}}
\right\vert_{z\ =\ 0}} \!\!\!\!\!& = & \!\!\!\!\!\ol{\fermi\pars{0}} & \mbox{if} & \verts{a} < 1
\\[3mm]
\ol{\left.-\,{1 \over 2\pi\ic}\,2\pi\ic\,
{\fermi\pars{z} \over \ol{a}\pars{z - 1/\ol{a}}}
\right\vert_{z\ =\ 0}}\
-\
\ol{\left.\,{1 \over 2\pi\ic}\,2\pi\ic\,{\fermi\pars{z} \over \ol{a}z}
\right\vert_{z\ =\ 1/\ol{a}}} \!\!\!\!\!
& = & \!\!\!\!\!
\ol{\fermi\pars{0}} - \ol{\fermi\pars{1 \over \ol{a}}} & \mbox{if} & \verts{a} > 1
\end{array}\right.
\end{align}
Tenga en cuenta que se trata de un cambio de signo entre el final de la línea $\pars{1}$ y el
comienzo de la línea $\pars{2}$ desde la conjugación de cambiar el sentido de rotación que nos 'flojos' indica con $\ds{\color{#c00000}{\LARGE\ol{z}}}$ en la línea $\pars{1}$.
\begin{align}&\color{#66f}{\large{1 \over 2\pi\ic}\int_{\verts{z}\ =\ 1}{\ol{\fermi\pars{z}} \over z - a} \,\dd z
=
\left\lbrace\begin{array}{lcl}
\ol{\fermi\pars{0}} & \quad\mbox{if}\quad & \verts{a} < 1
\\[3mm]
\ol{\fermi\pars{0}} - \ol{\fermi\pars{1 \over \ol{a}}}
& \quad\mbox{if}\quad & \verts{a} > 1
\end{array}\right.}
\end{align}