On the representation functions of certain numeration systems

Abstract

Let $\beta>1$ be fixed. We consider the $(\frak{b, d})$ numeration system, where the base ${\frak b}=(b_k)_{k\geq 0}$ is a sequence of positive real numbers satisfying $\lim_{k\rightarrow \infty}b_{k+1}/b_k=\beta$, and the set of digits ${\frak d}\ni 0$ is a finite set of nonnegative real numbers with at least two elements. Let $r_{\frak{b, d}}(\lambda)$ denote the number of representations of a given $\lambda\in\mathbb{R}$ by sums $\sum_{k\ge 0}\delta_kb_k$ with $\delta_k$ in ${\frak d}$. We establish upper bounds and asymptotic formulas for $r_{\frak{b,d}}(\lambda)$ and its arbitrary moments, respectively. We prove that the associated zeta function $\zeta_{\frak{b, d}}(s):=\sum_{\lambda>0}r_{\frak{b, d}}(\lambda)\lambda^{-s}$ can be meromorphically continued to the entire complex plane when $b_k=\beta^{k}$, and to the half-plane $\Re(s)>\log_\beta |\frak{d}|-\gamma$ when $b_k=\beta^{k}+O(\beta^{(1-\gamma)k})$, with any fixed $\gamma\in(0,1]$, respectively. We also determine the possible poles, compute the residues at the poles, and locate the trivial zeros of $\zeta_{\frak{b, d}}(s)$ in the regions where it can be extended. As an application, we answer some problems posed by Chow and Slattery on partitions into distinct terms of certain integer sequences.