An integral approach to the Gardner-Fisher and untwisted Dowker sums

TL;DR

This paper introduces an integral method for efficiently computing Gardner-Fisher and related trigonometric power sums, confirming previous empirical results and deriving new number theoretic formulas and identities.

Contribution

The paper presents a novel integral approach to evaluate trigonometric power sums, extending to related sums and deriving new formulas for Nörlund polynomials and symmetric polynomials.

Findings

Confirmed earlier empirical results with a more efficient method

Derived new formulas for Nörlund polynomials at specific values

Established connections between sums and symmetric polynomials

Abstract

We present a new and elegant integral approach to computing the Gardner-Fisher trigonometric power sum, which is given by $$ S_{m,v}=\left(\frac \pi{2m}\right)^{2v}\sum_{k=1}^{m-1}\cos^{-2v}\left(\frac{k\pi}{2m}\right)\, , $$ We present a new and elegant integral approach to computing the Gardner-Fisher trigonometric power sum, which is given by $$ S_{m,v}=\left(\frac \pi{2m}\right)^{2v}\sum_{k=1}^{m-1}\cos^{-2v}\left(\frac{k\pi}{2m}\right)\, , $$ where $m$ and $v$ are positive integers. This method not only confirms the results obtained earlier by an empirical method, but it is also much more expedient from a computational point of view. By comparing the formulas from both methods, we derive several new interesting number theoretic results involving symmetric polynomials over the set of quadratic powers up to $(v-1)^2$ and the generalized cosecant numbers. The method is then extended to other related trigonometric power sums including the untwisted Dowker sum. By comparing both forms for this important sum, we derive new formulas for specific values of the N\"{o}rlund polynomials. Finally, by using the results appearing in the tables, we consider more advanced sums involving the product of powers of cotangent and tangent with powers of cosecant and secant respectively.