[Click here for a PDF version of this post, and the previous posts in this series.] We used a complicated limiting argument to show that the \( \mathrm{sgn}(x – x’) \) factor in the contour integral derivation of the Helmholtz operator Green’s function was wrong. Having discovered, even if slightly by accident, what the correct … Continue reading A trilogy in 7+ parts: A better check of the 1D Helmholtz Green’s function.