A Banach algebra of generalized functions

An algebraic isomorphism from a convolution algebra of Laplace transformable functions with support on the half-line to a complete discrete normed convolution algebra of sequences is used to construct generalized functions. The extension of this function-to-sequence map to a commutative Banach algebra of generalized functions is shown to be a Banach algebra isomorphism which can be utilized to establish a discrete formulation of a Mikusiński-type operational calculus and to construct algorithms for the numerical solution of half-line convolution equations.     

Preduals of von Neumann Algebras

Proofs of two assertions are sketched. 1) If the Banach space of a von Neumann algebra A is the third dual of some Banach space, then the space A is isometrically isomorphic to the second dual of some von Neumann algebra A and the von Neumann algebra A is uniquely determined by its enveloping von Neumann algebra (up to von Neumann algebra isomorphism) and is the unique second predual of A (up to isometric isomorphism of Banach spaces). 2) An infinite-dimensional von Neumann algebra cannot have preduals of all orders.     

Description of some classes of Leibniz algebras

In this paper we describe the isomorphism classes of finite-dimensional complex Leibniz algebras whose quotient algebra with respect to the ideal generated by squares is isomorphic to the direct sum of three-dimensional simple Lie algebra sl₂ and a three-dimensional solvable ideal. We choose a basis of the isomorphism classes’ representatives and give explicit multiplication tables.     

Structure of the Loday–Ronco Hopf algebra of trees

Loday and Ronco defined an interesting Hopf algebra structure on the linear span of the set of planar binary trees. They showed that the inclusion of the Hopf algebra of non-commutative symmetric functions in the Malvenuto–Reutenauer Hopf algebra of permutations factors through their Hopf algebra of trees, and these maps correspond to natural maps from the weak order on the symmetric group to the Tamari order on planar binary trees to the boolean algebra.We further study the structure of this Hopf algebra of trees using a new basis for it. We describe the product, coproduct, and antipode in terms of this basis and use these results to elucidate its Hopf-algebraic structure. In the dual basis for the graded dual Hopf algebra, our formula for the coproduct gives an explicit isomorphism with a free associative algebra. We also obtain a transparent proof of its isomorphism with the non-commutative Connes–Kreimer Hopf algebra of Foissy, and show that this algebra is related to non-commutative symmetric functions as the (commutative) Connes–Kreimer Hopf algebra is related to symmetric functions.     

The Ring of Modules with Endo-permutation Source

In this paper we consider certain subalgebras of the Green algebra (representation algebra) of a finite group G. One such algebra is spanned by the isomorphism classes of all indecomposable modules whose source is an endo-permutation module. This algebra can be embedded into a finite direct product of Laurent polynomial rings in finitely many variables over a field. Another such algebra is spanned by the isomorphism classes of all irreducibly generated modules. When G is p-solvable then this algebra is finite-dimensional and split semisimple.R. Boltje was supported by the NSF, DMS-0200592 and 0128969. B. Külshammer was supported by the DAAD.     

Linear maps preserving zero products on nest subalgebras of von Neumann algebras

In this paper, it is proved that every surjective linear map preserving identity and zero products in both directions between two nest subalgebras with non-trivial nests of any factor von Neumann algebra is an isomorphism; and that every surjective weakly continuous linear map preserving identity and zero Jordan products in both directions between two nest subalgebras with non-trivial nests of any factor von Neumann algebra is either an isomorphism or an anti-isomorphism.     

Hopf代数的结构定理和对映阶数

本文中，我们把Ｈｏｐｆ代数的结构定理推广到Ｈｏｐｆ代数意义下的同构，从而给出Ｈｏｐｆ代数既约分支的对映阶数，并得到Ｈｏｐｆ代数扩张的对映阶数是任意的．这部分回答了Ｅ．Ｊ．Ｔａｆｔ１９９４年提出的一个问题．     

Atiyah–Bott index on stratified manifolds

In this paper, the Poincaré isomorphism in K-theory on manifolds with edges is constructed. It is shown that the Poincaré isomorphism can be naturally constructed in terms of noncommutative geometry. More precisely, we obtain a correspondence between a manifold with edges and a noncommutative algebra and establish an isomorphism between the K-group of this algebra and the K-homology group of the manifold with edges, which is considered as a compact topological space.     

布尔代数上的Fuzzy同余关系

引入了布尔代数上的Fuzzy同余关系的概念,讨论了布尔代数上的Fuzzy同余关系与布尔代数的Fuzzy理想之间的关系,给出了商布尔代数的同构定理。     

Isomorphism Classes of Rings Related to Heisenberg Algebras

Abstract

In this paper we examine isomorphism classes of algebras which are generalizations of the enveloping algebra of the Heisenberg Lie algebra.     

量子环面上一类导子李代数的结构和自同构群

本文研究量子环面上的一类导子李代数,它包含了Virasoro-Like代数及其q类似．首先证明了这 类导子李代数之间的同构一定是分次同构,并进一步给出了代数同构的充要条件及同构映射的具体表达 式,最后确定了该类李代数的自同构群．     

Fuzzy代数与Fuzzy商代数

本文更深入地讨论了Ｆｕｚｚｙ代数，Ｆｕｚｚｙ理想的性质，定义了Ｆｕｚｚｙ商代数，并证明了代数Ｙ关于代数Ｚ的同态ｆ－１［Ｏｚ］的Ｆｕｚｚｙ商代数与代数Ｚ同构等性质。     

On the Poincaré isomorphism in <Emphasis Type="Italic">K</Emphasis>-theory on manifolds with edges

In this paper, the Poincaré isomorphism in K-theory on manifolds with edges is constructed. It is shown that the Poincaré isomorphism can be naturally constructed in terms of noncommutative geometry. More precisely, we obtain a correspondence between a manifold with edges and a noncommutative algebra and establish an isomorphism between the K-group of this algebra and the K-homology group of the manifold with edges, which is considered as a compact topological space.     

Whittaker modules for a Lie algebra of Block type

In this paper, we study Whittaker modules for a Lie algebra of Block type. We define Whittaker modules and under some conditions, obtain a bijective correspondence between the set of isomorphism classes of Whittaker modules over this algebra and the set of ideals of a polynomial ring, parallel to a result from the classical setting and the case of the Virasoro algebra.     

有限复杂度的Koszul代数

首先给出了Koszul代数的张量积的复杂度,然后研究了Koszul遗传代数上的Koszul单列模,并证明了Koszul遗传代数上的Koszul模M的Koszul合成列在同构意义下是唯一的.     

Affine varieties and lie algebras of vector fields

In this article, we associate to affine algebraic or local analytic varieties their tangent algebra. This is the Lie algebra of all vector fields on the ambient space which are tangent to the variety. Properties of the relation between varieties and tangent algebras are studied. Being the tangent algebra of some variety is shown to be equivalent to a purely Lie algebra theoretic property of subalgebras of the Lie algebra of all vector fields on the ambient space. This allows to prove that the isomorphism type of the variety is determinde by its tangent algebra.     

Translation-invariant integrals,and Fourier analysis on Clifford and Grassmann algebras

The generalization of Berezin's Grassmann algebra integral to a Clifford algebra is shown to be translation-invariant in a certain sense. This enables the construction of analogs of twisted convolutions of Grassmann algebra elements and of the Fourier-Weyl transformation, which is an isomorphism from a Clifford algebra to the Grassmann algebra over the dual space, equipped with a twisted convolution product. As an application a noncommutative central limit theorem for states of a Clifford algebra is proved.     

Localization algebras and the coarse Baum--Connes conjecture

We introduce a localization algebra to define a local index mapo from K-homology to the K-theory of the localization algebra. we show that the local index map is an isomorphism. We apply this result to study the coarse Baum-Connes conjecture.     

Doi-Hopf模以及其上的平坦联络

对于任意Hopf代数,在其上建立了一种新的具有非交换微分几何形式的代数结构,并论证了Doi-hopf模与具有平坦联络的模之间是同构的,其中,联络对应于我们所给的微分算子.