English

A New Linear Inversion Formula for a class of Hypergeometric polynomials

Classical Analysis and ODEs 2020-07-07 v1

Abstract

Given complex parameters xx, ν\nu, α\alpha, β\beta and γN\gamma \notin -\mathbb{N}, consider the infinite lower triangular matrix A(x,ν;α,β,γ)\mathbf{A}(x,\nu;\alpha, \beta,\gamma) with elements An,k(x,ν;α,β,γ)=(1)k(n+αk+α)F(kn,(β+n)ν;(γ+n);x) A_{n,k}(x,\nu;\alpha,\beta,\gamma) = \displaystyle (-1)^k\binom{n+\alpha}{k+\alpha} \cdot F(k-n,-(\beta+n)\nu;-(\gamma+n);x) for 1kn1 \leqslant k \leqslant n, depending on the Hypergeometric polynomials F(n,;;x)F(-n,\cdot;\cdot;x), nNn \in \mathbb{N}^*. After stating a general criterion for the inversion of infinite matrices in terms of associated generating functions, we prove that the inverse matrix B(x,ν;α,β,γ)=A(x,ν;α,β,γ)1\mathbf{B}(x,\nu;\alpha, \beta,\gamma) = \mathbf{A}(x,\nu;\alpha, \beta,\gamma)^{-1} is given by \begin{align} B_{n,k}(x,\nu;\alpha, \beta,\gamma) = & \; \displaystyle (-1)^k\binom{n+\alpha}{k+\alpha} \; \cdot \nonumber \\ & \; \biggl [ \; \frac{\gamma+k}{\beta+k} \, F(k-n,(\beta+k)\nu;\gamma+k;x) \; + \nonumber \\ & \; \; \; \frac{\beta-\gamma}{\beta+k} \, F(k-n,(\beta+k)\nu;1+\gamma+k;x) \; \biggr ] \nonumber \end{align} for 1kn1 \leqslant k \leqslant n, thus providing a new class of linear inversion formulas. Functional relations for the generating functions of related sequences SS and TT, that is, T=A(x,ν;α,β,γ)SS=B(x,ν;α,β,γ)TT = \mathbf{A}(x,\nu;\alpha, \beta,\gamma) \, S \Longleftrightarrow S = \mathbf{B}(x,\nu;\alpha, \beta,\gamma) \, T, are also provided.

Keywords

Cite

@article{arxiv.2007.01865,
  title  = {A New Linear Inversion Formula for a class of Hypergeometric polynomials},
  author = {Ridha Nasri and Alain Simonian and Fabrice Guillemin},
  journal= {arXiv preprint arXiv:2007.01865},
  year   = {2020}
}

Comments

16 pages. arXiv admin note: substantial text overlap with arXiv:1904.08283, arXiv:1909.09694

R2 v1 2026-06-23T16:50:22.683Z