Generalizations of Euler's Theorem to $k$-regular partitions
Hongshu Lin, Wenston J. T. Zang
TL;DR
The paper generalizes Euler's partition theorem to $k$-regular partitions by introducing $E_k(n)$ and proving $|B_k(n)|=|E_k(n)|$, extending classical equinumerosity results. It also establishes $|B'_k(n)|=|C_k(n+1)|$ through both a generating-function approach and a separate bijective proof, enriching the landscape of partition identities. The methods yield new combinatorial constructions and $q$-series identities, with $k=2$ recovering familiar Euler-type correspondences while providing novel perspectives on partition bijections and their analytic counterparts.
Abstract
Let $A_k(n)$ denote the set of $k$-distinct partitions of $n$, and let $B_k(n)$ be the set of $k$-regular partitions of $n$. Glaisher showed that $\# A_k(n) = \# B_k(n)$. For $k=2$, this equality yields the celebrated Euler's partition theorem. In this paper, we present a new partition set $E_k(n)$, which is equinumerous to $B_k(n)$.
