Mod 7 Cohomology Algebra of Held Simple Group

We calculate the mod7 cohomology algebra of the Held simple group, whose Sylow 7-subgroups are extraspecial of order 7³ and exponent 7. Our method depends on the analysis of the Carlson module of a regular class belonging to a system of parameters.     

Relative Projectivity of Modules and Cohomology Theory of Finite Groups

In the modular representation theory of finite groups the theory of projectivity relative to subgroups is of fundamental importance. To generalize this notion the theory of projectivity relative to modules was introduced by the first author. Our aim is to show some aspects of cohomology theory of finite groups concerning projectivity of modules relative to both subgroups and modules. We shall give some applications to the cohomology theory; especially we shall calculate the mod 2 cohomology algebras of finite groups with wreathed Sylow 2-subgroups.     

First Cohomology Group from the Virasoro-Like Algebra to its Larsson Functor Module

Let 𝒲 be the Virasoro-like algebra, and d ₁, d ₂ be the degree derivations of 𝒲. Set ? = W⊕C d ₁⊕C d ₂. Let F ^α(V) be the ?-module defined by Larsson's functor applied to a finite dimensional sl ₂-module V. In this article, the derivations from ? to ?-modules F ^α(V) and the first cohomology group H ¹(?, F ^α(V)) are given.     

模p Steenrod代数上同调的一些注记

模p Steenrod代数A的上同调H~(s,t)(A)是决定球面稳定同伦群的最有力数据.首先给出了模p Steenrod代数A和May谱序列的一些重要结论,而后给出与乘积元γ_(s+3)l_ng_0∈H~(s+8,t(s,n))(A)密切相关的May谱E_1项的结果,这些结论对该乘积元的非平凡性研究有重要意义,其中t(s,n)=p~(n+1)q+2p~nq+(s+3)p~2q+(s+3)pq+(s+3)q+s, 0≤sp-6, n≥4, p≥11, q=2(p-1).     

模p-Steenrod代数高维上同调群中的一个非平凡乘积元

证明了模p-Steenrod代数高维上同调群中的乘积元b_0~2γs∈Ext_A~(s+4,t(s))(Z_p,Z_p)的非平凡性,其中p≥11,3≤sp-1,t(s)=2(p-1)[sp~2+(s+1)p+(s-2)]+(s-3).     

极大三角代数的交换子和上同调

设M为闭极大三角代数S的σ-弱闭双边模且满足MS,证明了模M交换子C(A,M)= M．进而,如果MAlgLat S,得到H~n(S,AlgLat S)=H~n(S,M)(n≥1)；若dimH〧≤1,则H~n(S,M)=0．     

Cohomology of a Poisson Algebra

We propose a technique for calculating the cohomology of a Poisson algebra using the Laplace transformation of distributions with compact support. We find the lowest-order cohomologies of this algebra with coefficients in two natural representations: the trivial and the adjoint representations.     

Fibonacci代数平凡扩张的一阶Hochschild上同调群

基于Cibils等人对单项式代数的向量空间Alt(DΛ)的组合描绘,得到了Fibonacci代数平凡扩张的一阶Hochschild上同调群的维数.     

Homological Algebra for Coalgebraic Modules and Mod p K-Theory of Infinite Loop Spaces

In this paper, we develop the theory of homological algebra for coalgebraic modules, and compute and p K-theory of infinite loop spaces associated to BP-module spectra.     

Cohomology of Pure Braid Groups of exceptional cases

Consider the ring R:=Q[τ,τ−1] of Laurent polynomials in the variable τ. The Artin's Pure Braid Groups (or Generalized Pure Braid Groups) act over R, where the action of every standard generator is the multiplication by τ. In this paper we consider the cohomology of these groups with coefficients in the module R (it is well known that such cohomology is strictly related to the untwisted integral cohomology of the Milnor fibration naturally associated to the reflection arrangement). We compute this cohomology for the cases I₂(m), H₃, H₄, F₄ and An with 1?n?7.     

On the Generalized Enveloping Algebra of a Color Lie Algebra

Let G be an abelian group, ε an anti-bicharacter of G and L a G-graded ε Lie algebra (color Lie algebra) over a field of characteristic zero. We prove that for all G-graded, positively filtered A such that the associated graded algebra is isomorphic to the G-graded ε-symmetric algebra S(L), there is a G- graded ε-Lie algebra L and a G-graded scalar two cocycle , such that A is isomorphic to U _ω (L) the generalized enveloping algebra of L associated with ω. We also prove there is an isomorphism of graded spaces between the Hochschild cohomology of the generalized universal enveloping algebra U(L) and the generalized cohomology of the color Lie algebra L. Supported by the EC project Liegrits MCRTN 505078.     

A Note on the Associated Primes of Local Cohomology Modules

In this note we give a simple proof of the following result: Let R be a commutative Noetherian ring,  an ideal of R and M a finite R-module, if H_ ⁱ (M) has finite support for all i < n, then Ass(H_ ⁿ (M)) is finite.     

关于广义分次局部上同调的tame性的一个结果

设R=＋n∈N0Rn（R=R0[R1]）是分次Noether交换环,（R0,m0）是一个局部环,R＋=＋n∈NRn;设N是一个有限生成Z-分次R-模,这里N、N0、Z分别表示全体正整数、全体非负整数和全体格致所构成的集合．令h=sup{i∈Z｜HR＋^i（N）不是Artin模}．Dibaei和Nazari证明了HR＋^h（N）是tame模．我们将该结果推广到了广义分次局部上同调模的情形．     

From the Potential to the First Hochschild Cohomology Group of a Cluster Tilted Algebra

Algebras and Representation Theory - The objective of this paper is to give a concrete interpretation of the dimension of the first Hochschild cohomology space of a cyclically oriented or tame...     

The Cohomology of the Universal Steenrod Algebra

The mod 2 universal Steenrod algebra Q is a homogeneous quadratic algebra closely related to the ordinary mod 2 Steenrod algebra and the Lambda algebra introduced in [1]. In this paper we show that Q is Koszul. It follows by [7] that its cohomology, being purely diagonal, is isomorphic to a completion of Q itself with respect to a suitable chain of two-sided ideals.