Separable overpartition classes and the $r$-chain excludant sizes of an overpartition
Y. H. Chen, Thomas Y. He, H. X. Huang, X. Zhang
TL;DR
This paper addresses overpartitions by studying the $r$-chain excludant sizes, denoted $mes(\pi; r)$ and $maes(\pi; r)$, and by introducing two separable overpartition classes, $L_k$-overpartitions and $F_k$-overpartitions. It connects $mes$ and $maes$ to the $(r+1)$-repeating size through conjugation and derives generating-function formulas for the aggregated statistics $\sigma_r{mes}(n)$ and $\sigma_r{maes}(n)$. It then defines $L_k$- and $F_k$-overpartitions as separable classes, proves their separability, and provides explicit generating functions that yield the $L_k$ and $F_k$ formulas. Overall, the work extends the separable-class framework to overpartitions and supplies closed-form generating functions for these new overpartition families.
Abstract
An overpartition is a partition such that the first occurrence (equivalently, the last occurrence) of a number may be overlined. In this article, we will investigate two contents of overpartitions. We first consider the $r$-chain minimal and maximal excludant sizes of an overpartition. Then, we introduce $L_k$-overpartitions and $F_k$-overpartitions, which are two types of separable overpartition classes.
