A New Grounded Partition Identity of Type $D_4^{(3)}$

In this paper, we prove a new Rogers-Ramanujan-type identity, involving grounded partitions, by computing a character of the affine Kac-Moody algebra $D_4^{(3)}$ in two different ways. The product side is derived using Lepowsky’s product formula, while the sum side is obtained using perfect crystals with a technique of Dousse and Konan.