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I'm attempting to justify existence of the following integral stated in $Proposition \, \, 1$, my approach can be seen withen $Lemma\, \, \, 1.)$
$$ \, \, \, \, \, \, \, Proposition \, \, 1$$
$$1.) \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \oint_{\gamma r}z^{n}dz=\int_{0}^{2 \pi}r^{n}e^{...