Bulletin of the
Korean Mathematical Society BKMS

In this paper, we study the Green ring $r(\mathfrak{w}^0_n)$ of the weak Hopf algebra $\mathfrak{w}^0_n$ based on Taft Hopf algebra $H_n(q)$. Let $R(\mathfrak{w}^0_n):=r(\mathfrak{w}^0_n)\otimes_\mathbb{Z}\mathbb{C}$ be the Green algebra corresponding to the Green ring $r(\mathfrak{w}^0_n)$. We first determine all finite dimensional simple modules of the Green algebra $R(\mathfrak{w}^0_n)$, which is based on the observations of the roots of the generating relations associated with the Green ring $r(\mathfrak{w}^0_n)$. Then we show that the nilpotent elements in $r(\mathfrak{w}^0_n)$ can be written as a sum of finite dimensional indecomposable projective $\mathfrak{w}^0_n$-modules. The Jacobson radical $J(r(\mathfrak{w}^0_n))$ of $r(\mathfrak{w}^0_n)$ is a principal ideal, and its rank equals $n-1$. Furthermore, we classify all finite dimensional non-simple indecomposable $R(\mathfrak{w}^0_n)$-modules. It turns out that $R(\mathfrak{w}^0_n)$ has $n^2-n+2$ simple modules of dimension 1, and $n$ non-simple indecomposable modules of dimension 2.

Keywords: Weak Hopf algebra, representation

MSC numbers: Primary 13C05, 16D70

Supported by: This work was financially supported by National Natural Science Foundation of China 12371041 and Scientific Research and Innovation Project of Graduate Students in Jiangsu Province (Grant No. KYCX22-3448).