English

On the Cauchy transform of complex powers of the identity function

Complex Variables 2024-01-17 v2

Abstract

The integral z=1zβzαdz\int_{|z|=1} \frac{z^\beta}{z-\alpha} dz for β=12\beta=\frac{1}{2} has been comprehensively studied by Mortini and Rupp for pedagogical purposes. We write for a similar purpose, elaborating on their work with the more general consideration βC\beta \in \mathbb{C}. This culminates in an explicit solution in terms of the hypergeometric function for α1|\alpha| \neq 1 and any βC\beta \in \mathbb{C}. For rational β\beta, the integral is reduced to a finite sum. A differential equation in α\alpha is derived for this integral, which we show has similar properties to the hypergeometric equation.

Keywords

Cite

@article{arxiv.2209.07649,
  title  = {On the Cauchy transform of complex powers of the identity function},
  author = {Benjamin Faktor and Michael Kuhn and Gahl Shemy},
  journal= {arXiv preprint arXiv:2209.07649},
  year   = {2024}
}

Comments

18 pages, 3 figures