A note on trigonometric polynomials for lower bounds of $\zeta(s)$
Non-negative trigonometric polynomials satisfying certain properties are employed when studying a number of aspects of the Riemann zeta function. When establishing zero-free regions in the critical strip, the classical polynomial $3+4\cos(\theta)+\cos(2\theta)$ used by de la Vallée Poussin has since been replaced by more beneficial polynomials with larger degree. The classical polynomial was also employed by Titchmarsh to provide a lower bound on $\abs{\zeta(\sigma+it)}$ when $\sigma>1$. We show that this polynomial is optimal for this purpose.
Authors
- Nicol Leong (ORCID: https://orcid.org/0000-0001-7064-2592)
- Michael J. Mossinghoff (ORCID: https://orcid.org/0000-0002-7983-5427)
Publication Details
- Journal
- Functiones et Approximatio Commentarii Mathematici
- Published
- 2025-03-14
- DOI
- https://doi.org/10.7169/facm/240408-31-12
- Citations
- 1
- Primary Topic
- Analytic Number Theory Research
- Type
- article
- Field-Weighted Citation Impact
- 5.38