English

Recurrence relations for the coefficients of the confluent and Gauss hypergeometric functions in the complex plane

Complex Variables 2026-01-16 v1 Classical Analysis and ODEs

Abstract

For a,b,c,z,p,θCa,b,c,z,p, \theta \in \mathbb{C}, where C\mathbb{C} is the complex plane, cN{0}-c\notin \mathbb{N\cup }\left\{ 0\right\} , let \begin{equation*} \mathcal{M}\left( z\right) =\left( 1-\theta z\right) ^{p}M\left(a;c;z\right) =\sum_{n=0}^{\infty }u_{n}z^{n}, \end{equation*} where z<1θ|z| <\frac{1}{\theta}, arg(1θz)<π|\arg (1-\theta z)| < \pi, and let \begin{equation*} \mathcal{G}\left( z\right) =(1-\theta z) ^{p}F(a,b;c;z) =\sum_{n=0}^{\infty }v_{n} z^{n}, \end{equation*} where z<1|z| < 1, arg(1θz)<π|\arg (1-\theta z)| < \pi. In this paper, we prove that the coefficients unu_{n} and vnv_{n} for n0n\geq 0 satisfy a 3-order recurrence relation. These offer a new way to study confluent hypergeometric function M(a;c;z)M(a;c;z) and Gauss hypergeometric function F(a,b;c;z)F(a,b;c;z). And we provide other special functions' recurrence relations of their coefficients, such as error function, Bessel function, incomplete gamma function, complete elliptic integral and Chebyshev polynomials.

Keywords

Cite

@article{arxiv.2601.10040,
  title  = {Recurrence relations for the coefficients of the confluent and Gauss hypergeometric functions in the complex plane},
  author = {Zi-Qiao Xu and Zhong-Xuan Mao and Jing-Feng Tian},
  journal= {arXiv preprint arXiv:2601.10040},
  year   = {2026}
}