Gorenstein代数上的Hopf代数作用

令H是有限维Hopf代数，A是左H-模代数。本文证明了A是Gorenstein代数的充分必要条件。A^H也是Gorenstein代数的条件。它是Enochs EE,GarciaJJ和del RioA关于群作用相应的理论的推广，同时给出A/A^H是Frobenius扩张的条件。     

量子包络代数借助Hopf代数的扩张

设H是Hopf代数,g是由Cartan矩阵A=(a_(ij))_(I×I)决定的广义Kac-Moody代数,这里的I是指标集,它或者是有限个整数{1,2,…,n},或者是整个自然数集N,用f,g表示从I到Hopf代数H的群象元素集G(H)两个映射,假如集合{f(i),g(i)|i∈I}中任何两个元素乘法可以交换,则可以在H(?)_g~f U_q(g)上定义一种Hopf结构,这里的U_q(g)是g量子包络代数.     

Hopf代数的扭曲余积和H^R型Hopf代数

本文引进了Ｈｏｐｆ代数的扭曲余积，推广了广义偶交叉积，使得一般的右Ｓｍａｓｈ余积也是这里的特殊情况，讨论了Ｈ＾Ｒ型Ｈｏｐｆ代数与扭曲余积的关系。     

Hopf代数余作用

对于Ｈｏｐｆ代数Ｈ上的余模代数Ａ,当Ｈ是有限维或幺模（ｕｎｉｍｏｄｕｌａｒ）时,存在由交叉积Ａ＃Ｈ^＊ｒａｔ和余不变子代数Ａ^ｃｏＨ构成的Ｍｏｒｉｔａ Ｃｏｎｔｅｘｔ．本文论证了对于任意的Ｈｏｐｆ代数Ｈ,结果仍是成立的     

辫子Hopf代数的积分

本文引进了无限维辫子Hopf代数日的忠实拟对偶H~d和严格拟对偶H~(d′)．证明了每个严格拟对偶H~(d′)是一个H-Hopf模．发现了H~d的极大有理H~d-子模H~(drat)与积分的关系,即：H~(drat)≌∫_(H~d)~l■H．给出了在Yetter-Drinfeld范畴(_B~ByD,C)中的辫子Hopf代数的积分的存在性和唯—性．     

Hopf代数的扭曲余积和H￣R型Hopf代数

本文引进了Ｈｏｐｆ代数的扭曲余积，推广了广义偶交叉积，使得一般的右Ｓｍａｓｈ余积也是这里的特殊情况，讨论了Ｈ￣Ｒ型Ｈｏｐｆ代数扭曲余积的关。     

带弱内射的Hopf代数结构

利用已知Hopf代数构造新的Hopf代数是Hopf代数理论中最基本的问题之一．该文给出了Smash积A#H为Hopf代数，H是A#H的商Hopf代数， 且具有弱内射H→A#H的充分必要条件．易证，此种构造推广了Radford和Majid等人所构造的双积和双交叉积等结构．     

弱Hopf代数的扭曲理论

本文研究了弱Hopf代数的扭曲理论的对偶问题.利用了弱Hopf代数上的弱Hopf双模的(辫子)张量范畴与扭曲弱Hopf代数上的弱Hopf双模的(辫子)张量范畴等价方法,得到Long模范畴是Yetter-Drinfel'd模范畴的辫子张量子范畴.推广了Oeckl(2000)的结果.     

辫子Hopf代数的因子分解

我们获得了辫子双代数和辫子Hopf代数的双重分解, 给出了辫子Hopf代数的积分和半单性与它的因子的积分和半单性之间的关系.     

Hopf代数的Kaplansky十大猜想的一些新进展

本文介绍了Hopf代数中众所周知的Kaplansky十大猜想及其进展.     

弱Hopf代数作用与冲积

本文研究了弱Hopf代数上的冲积并讨论了它约性质．设H是弱Hopf代数,A是左H-摸代数．我们给出了冲积A#H是弱双代数的一个充分条件以及A#H是A可分扩张的一个判定条件．另外,利用积分理论研究了Hopf模代数的有限性条件．     

Commutative Algebras with Radical Cube Zero

Abstract

We present “canonical forms” of finite dimensional (quasi-Frobenius) commutative algebras Λ over a field k such that the radical cubed is zero and Λ modulo the radical is a product of copies of k. We also determine the isomorphism classes of the algebras Λ over some typical fields.     

On Galois Coverings of the Enveloping Algebras of Self-Injective Nakayama Algebras

Abstract

There is constructed a Galois covering F of the enveloping K-algebra A ^e of a self-injective Nakayama K-algebra A such that the right A ^e -module A is of the first kind with respect to F. Then, with the help of the constructed Galois covering, the Auslander-Reiten translation period of A is computed.     

Structure Theorems for Bicomodule Algebras Over Quasi-Hopf Algebras,Weak Hopf Algebras,and Braided Hopf Algebras

Let H be a quasi-Hopf algebra, a weak Hopf algebra, or a braided Hopf algebra. Let B be an H-bicomodule algebra such that there exists a morphism of H-bicomodule algebras v: H → B. Then we can define an object B^co(H), which is a left-left Yetter–Drinfeld module over H, having extra properties that allow to make a smash product B^co(H)#H, which is an H-bicomodule algebra, isomorphic to B.     

Hopf-Type Algebras

In this article, we provide an alternative approach to the definition of a weak Hopf algebra (WHA). For an associative unital algebra A with a coassociative comultiplication Δ ∈Alg ^u (A, A ? A), the set of homomorphisms from A to A ? A, which do not preserve the units. If the linear maps Ξ₁, Ξ₂ ∈ End(A ? A), defined by Ξ₁(a ? b) = Δ(a)(1 ? b), Ξ₂(a ? b) = (a ? 1)Δ(b), are von Neumann regular elements in the ring End(A ? A) of endomorphisms of A ? A satisfying some appropriate assumptions, we call the A a Hopf-type algebra. We show the existence of a target, a source, a counit, and an antipode of A as in the usual WHA.     

On Hopf Algebras and Their Generalizations

We survey Hopf algebras and their generalizations. In particular, we compare and contrast three well-studied generalizations (quasi-Hopf algebras, weak Hopf algebras, and Hopf algebroids), and two newer ones (Hopf monads and hopfish algebras). Each of these notions was originally introduced for a specific purpose within a particular context; our discussion favors applicability to the theory of dynamical quantum groups. Throughout the note, we provide several definitions and examples in order to make this exposition accessible to readers with differing backgrounds.     

广义路代数与点Hopf代数

Most of pointed Hopf algebras of dimension p^m with large coradtical are shown to be generalized path algebras. By the theory of generalized path algebras, the representations, homological dimensions and radicals of these Hopf algebras are obtained. The relations between the radicals of path algebras and connectivity of directed graphs are given.