3 problems

Let $K$ be an algebraically closed field of characteristic zero, let $G$ be a finite abelian group, and let … Let $A$ be a finite-dimensional cocommutative cosemisimple Yetter–Drin…

Assume that $q$ is not a root of unity, that $(q,t_1,t_2)$ satisfies $t_1t_2q^n=1$ for some integer $n\geq 1$, and that $(1-t_1)(1-t_2)\ne 0$. Let $Y_n$ be the $4n$-dimensional rig…

Let $M\langle(xy,x)\rangle$, $M\langle(y,xy)\rangle$, and $W^{b_1,-1}$ denote the Yetter–Drinfeld modules introduced in the paper, and let $\mathfrak{B}(-)$ denote their Nichols al…