English

Tur\'an inequalities from Chebyshev to Laguerre polynomials

Classical Analysis and ODEs 2022-04-05 v1 Number Theory

Abstract

Let gg and hh be real-valued arithmetic functions, positive and normalized. Specific choices within the following general scheme of recursively defined polynomials \begin{equation*} P_n^{g,h}(x):= \frac{x}{h(n)} \sum_{k=1}^{n} g(k) \, P_{n-k}^{g,h}(x), \end{equation*} with initial value P0g,h(x)=1P_{0}^{g,h}(x)=1 encode information about several classical, widely studied polynomials. This includes Chebyshev polynomials of the second kind, associated Laguerre polynomials, and the Nekrasov--Okounkov polynomials. In this paper we prove that for g(n)=ng(n)=n and fixed hh we obtain orthogonal polynomial sequences for positive definite functionals. Let h(n)=nsh(n)=n^s with 0s10 \leq s \leq 1 . Then the sequence satisfies Tur\'an inequalities for x0x \geq 0.

Keywords

Cite

@article{arxiv.2204.01008,
  title  = {Tur\'an inequalities from Chebyshev to Laguerre polynomials},
  author = {Bernhard Heim and Markus Neuhauser and Robert Troeger},
  journal= {arXiv preprint arXiv:2204.01008},
  year   = {2022}
}