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Bibliographic Details
Main Authors: Klein, Christian, Sjöstrand, Johannes, Zerzeri, Maher
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.16542
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Table of Contents:
  • Asymptotic expressions for an integral appearing in the solution of a d-bar problem are presented. The integral is a solid Cauchy transform of a function with a rapidly oscillating phase with a small parameter $h$, $0<h\ll 1$. Whereas standard steepest descent approaches can be applied to the case where the stationary points of the phase $ω_{k}$, $k=1,\ldots, N$ are far from the singularity $ζ$ of the integrand, a polarization approach is proposed for the case that $|ζ-ω_{k}|<\mathcal{O}(\sqrt{h})$ for some $k$. In this case the problem is studied in $\mathbb{C}^{2}$ ($\widetildeω:=\overlineω$ is treated as an independent variable) on steepest descent contours. An application of Stokes' theorem allows for a decomposition of the integral into three terms for which asymptotic expressions in terms of special functions are given.