English

Moments of Gaussian hypergeometric functions over finite fields

Number Theory 2022-02-08 v2

Abstract

We prove explicit formulas for certain first and second moment sums of families of Gaussian hypergeometric functions n+1Fn_{n+1}F_n, n1n\ge1, over finite fields with qq elements where qq is an odd prime. This enables us to find an estimate for the value 6F5(1)_6F_5(1). In addition, we evaluate certain second moments of traces of the family of Clausen elliptic curves in terms of the value 3F2(1)_3F_2(-1). These formulas also allow us to express the product of certain 2F1_2F_1 and n+1Fn_{n+1}F_n functions in terms of finite field Appell series which generalizes current formulas for products of 2F1_2F_1 functions. We finally give closed form expressions for sums of Gaussian hypergeometric functions defined using different multiplicative characters.

Keywords

Cite

@article{arxiv.2111.08393,
  title  = {Moments of Gaussian hypergeometric functions over finite fields},
  author = {Ankan Pal and Bidisha Roy and Mohammad Sadek},
  journal= {arXiv preprint arXiv:2111.08393},
  year   = {2022}
}