= Schwinger parameterization
{c}
{title2=$A^{-v}=\Gamma(v)^{-1}\int_0^\infty t^{v-1}e^{-tA}dt$}
For $\operatorname{Re}A>0$ and $\operatorname{Re}v>0$, rescaling the defining <gamma function> integral proves this representation, with compatible complex-power branches. It turns denominator powers into exponential factors, making <Gaussian integrals> possible. Combining two parameters by their sum and ratio gives the usual <Feynman parameter> identity. Outside its convergence domain a further continuation or pole prescription is needed.
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