AI 中文总结
本文研究了右 H-简单左 H-余代数代数的自由性与可除性,证明了相对 (H,A)-Hopf 模的自由性,并给出了半单类别的特征化,同时给出了 A 的结构定理及维数关系。
AI 中文摘要
设 H 为一个指针型 Hopf 代数,令 A 为右 H-简单左 H-余代数代数。我们证明了每个相对 (H,A)-Hopf 模都是 A-模的自由模,并给出了当相对 (H,A)-Hopf 模的类别是半单的条件的特征化。我们还给出了当 H 和 A 是 N_0-逐次时的 A 的嵌入型结构定理。作为结果,我们证明如果 H 是有限维的且 A^{co H}=k,则 A 的维数整除 H 的维数。
英文摘要
Let $H$ be a pointed Hopf algebra and let $A$ be a right $H$-simple left $H$-comodule algebra. We show that every relative $(H,A)$-Hopf module is free as an $A$-module and that this freeness characterizes the class of pointed Hopf algebras. We give a criterion for the category of relative $(H,A)$-Hopf modules to be semisimple. We also show that $A$ can be embedded into a left $H$-comodule algebra of a specific form when $H$ and $A$ are $\mathbb{N}_0$-graded. As a consequence, we prove that if $H$ is finite-dimensional and $A^{\mathrm{co} H}=\Bbbk$, then $A$ is finite-dimensional and $\dim A$ divides $\dim H$.
Comments31 pages; added a section and an appendix