Hom-可计算余代数的局部化（英文）

本文研究了可计算余模和Hom-可计算余代数的局部化问题.利用局部化方法,得到了可计算余模和Hom-可计算余代数的等价条件,推广了余代数上局部化理论的发展.     

余倾斜余模和Hom-余倾斜余模的注记

本文证明了f-余倾斜余模的Bongartz引理,即一个偏f-余倾斜余模可以做成f-余倾斜余模.首先得到了f-余倾斜余模的性质以及C-余模和AT-模之间的函子同构.此外还研究了Hom-挠对和Hom-余倾斜余模.     

余代数上余倾斜余模的结构

研究了余代数上余倾斜余模的结构特征,证明了每个余倾斜余模都可以写成不可分解的两两非同构的余模的直和形式,每个余倾斜余模包含所有的内射不可分解模作为直和项.最后构造了余倾斜余模的两个例子.     

Hom-弱Hopf代数上的Hom-smash余积

本文研究了在Hom-Hopf代数上引入Hom-弱Hopf代数的问题.利用建立弱左H-Hom-余模双代数的方法,获得了Hom-smash余积的代数结构,并证明了Hom-smash余积是Hom-余代数和Hom-弱Hopf代数,推广了由Molnar定义的smash余积Hopf代数.     

π-模余代数与π-模余理想

主要讨论局部有限维的Hopfπ-代数H上π-模余代数与π-模余理想.给出了π-H-模余代数与π-H~*-余模代数之间的对偶关系,得到了π-H-模余理想的一个充分必要条件.     

关于MH中的Lie双代数和余Poisson-Hopf代数

本文研究余三角Ｈｏｐｆ代数余模范畴中的Ｌｉｅ双代数和余ＰｏｉｓｓｏｎＨｏｐｆ代数,我们主要讨论余三角Ｈｏｐｆ代数余模范畴中的Ｌｉｅ双代数和余Ｐｏｉｓｓｏｎ－Ｈｏｐｆ代数之间的关系。     

关于伪紧余代数、余挠对和弦余代数

本文利用箭图和拓扑伪紧空间研究了K-余代数及其表示.定义了域K上的伪紧K-余代数,研究了伪紧K-余代数和K-代数范畴之间的关系,研究了余挠对和余模逼近,描述了余倾斜余挠对.通过有限维的支撑子余代数和基本的路余代数研究了弦余代数.     

关于μ~H中的Lie双代数和余Poisson-Hopf代数(英文)

本文研究余三角 Ｈｏｐｆ代数余模范畴中的 Ｌｉｅ双代数和余 Ｐｏｉｓｓｏｎ－Ｈｏｐｆ代数．我们主要讨论余三角Ｈｏｐｆ代数余模范畴中的Ｌｉｅ双代数和余Ｐｏｉｓｓｏｎ－Ｈｏｐｆ代数之间的关系．     

有限内射维数的余倾斜余模(英文)

本文中,受C.Nastasescu etc.和Y.Miyashita思想的影响,定义了余代数的余倾斜余模,研究得出有限内射维数的余倾斜余模的一些结论.     

Lie余模和Lie双代数的构造

首先给出Lie余模的直和分解, 然后根据Lie余模理论由Lie余代数构造某些(三角)Lie双代数.     

On Gorenstein coalgebras

We investigate the comodule representation category over the Morita-Takeuchi context coalgebra Γ and study the Gorensteinness of Γ. Moreover, we determine explicitly all Gorenstein injective comodules over the Morita-Takeuchi context coalgebra Γ and discuss the localization in Gorenstein coalgebras. In particular, we describe its Gabriel quiver and carry out some examples when the Morita-Takeuchi context coalgebra is basic.     

Flat Comodules and Perfect Coalgebras

Stenström introduced the notion of flat object in a locally finitely presented Grothendieck category 𝒜. In this article we investigate this notion in the particular case of the category 𝒜 = C-Comod of left C-comodules, where C is a coalgebra over a field K. Several characterizations of flat left C-comodules are given and coalgebras having enough flat left C-comodules are studied. It is shown how far these coalgebras are from being left semiperfect. As a consequence, we give new characterizations of a left semiperfect coalgebra in terms of flat comodules. Left perfect coalgebras are introduced and characterized in analogy with Bass's Theorem P. Coalgebras whose injective left C-comodules are flat are discussed and related to quasi-coFrobenius coalgebras.     

(*)-Serial coalgebras

In this paper, we introduce the notion of (*)-serial coalgebras which is a generalization of serial coalgebras. We investigate the properties of (*)-serial coalgebras and their comodules, and obtain sufficient and necessary conditions for a basic coalgebra to be (*)-serial.     

Equivalences of comodule categories for coalgebras over rings

In this article we defined and studied quasi-finite comodules, the cohom functors for coalgebras over rings. Linear functors between categories of comodules are also investigated and it is proved that good enough linear functors are nothing but a cotensor functor. Our main result of this work characterizes equivalences between comodule categories generalizing the Morita-Takeuchi theory to coalgebras over rings. Morita-Takeuchi contexts in our setting is defined and investigated, a correspondence between strict Morita-Takeuchi contexts and equivalences of comodule categories over the involved coalgebras is obtained. Finally, we proved that for coalgebras over QF-rings Takeuchi's representation of the cohom functor is also valid.     

广义路余代数和广义对偶Gabriel定理

通过将箭图的每个顶点放置一个k-余代数,首先引进了广义路余代数的概念,其次给出了广义路余代数的一些基本性质,还讨论了同构问题.证明了两个正规广义路余代数是同构的当且仅当他们的箭图及对应顶点上的单余代数是同构的.对于满足Codim C_0■1余代数C,证明了对偶Wedderburn-Malcev定理成立.作为广义路余代数的一个应用,推广了点余代数的对偶Gabriel定理.     

Relative homological coalgebras

We study classes of relative injective and projective comodules and extend well-known results about projective comodules given in [7]. The existence of covers and envelopes by these classes of comodules is also studied and used to characterize the projective dimension of a coalgebra. We also compare this homological coalgebra with the very intensively studied homological algebra of the dual algebra (see [5]). This revised version was published online in June 2006 with corrections to the Cover Date.     

Gorenstein Coalgebras

We study a class of semiperfect coalgebras which generalizes Quasi-co-Frobenius coalgebras (from the point of view of the projective dimension). This class of coalgebras allows us to study a relative concept of injective comodule in terms of the cotensor functor, generalizing a well-known result about coflat comodules.     

Quasi-co-Frobenius Coalgebras. II

Abstract

We prove new characterizations of Quasi-co-Frobenius (QcF) coalgebras and co-Frobenius coalgebras. Among them, we prove that a coalgebra is QcF if and only if C generates every left and every right C-comodule. We also prove that every QcF coalgebra is Morita-Takeuchi equivalent to a co-Frobenius coalgebra.