I was wondering if anyone could tell me something about this contour integral i ran into it and i have no idea what it is any info on it would be nice. {\oint\oint\oint}_{lim_{k\rightarrow0}e^{-ki}}^{\infty}\prod_{k=1}^{\infty}tanh^{-1}\theta d\theta
That is supposed to be a volume contour integral (not sure how to do that) thanks!