Ramanujan expansions of arithmetic functions of several variables over $\mathbb{F}_{q}[T]$

Tianfang Qi, Su Hu

Published 2018-11-05Version 1

Let $\mathbb{A}=\mathbb{F}_{q}[T]$ be the polynomial ring over finite field $\mathbb{F}_{q}$, and $\mathbb{A}_{+}$ be the set of monic polynomials in $\mathbb{A}$. In this paper, we show that the arithmetic functions of multi-variables over $\mathbb{A}_{+}$ can be expanded through the polynomial Ramanujan sums and the unitary polynomial Ramanujan sums. These are analogues of classical results over $\mathbb{N}$ by Winter, Delange and T\'oth.