Equivariant Crossed Modules and Cohomology of Groups with Operators

Braided equivariant crossed modules and cohomology of $Γ$-modules

If $Γ$ is a group, then braided $Γ$-crossed modules are classified by braided strict $Γ$-graded categorial groups. The Schreier theory obtained for $Γ$-module extensions of the type of an abelian $Γ$-crossed module is a generalization of the theory of $Γ$-module extensions.

Crossed Bimodules over Rings and Shukla Cohomology

In this paper we present some applications of Ann-category theory to classification of crossed bimodules over rings, classification of ring extensions of the type of a crossed bimodule.

等变交叉复形的映射空间到分类空间II：一般拓扑群情形

Spaces of maps into classifying spaces for equivariant crossed complexes, II: The general topological group case

将前一篇关于交叉复形的等变同伦理论的结果从离散群推广到一般拓扑群。主要的新成分，这是必要的分析同伦相干理论的交叉复杂，使用详细的结果适当的艾伦伯格-齐伯理论从唐克斯的论文，其关系到单纯同伦相干。同样，我们的结果不仅提供信息的同伦分类的某些等变映射，但也对弱等变同伦类型的相应的等变函数空间。

Group cohomology with coefficients in a crossed-module

We compare three different ways of defining group cohomology with coefficients in a crossed-module: 1) explicit approach via cocycles; 2) geometric approach via gerbes; 3) group theoretic approach via butterflies. We discuss the case where the crossed-module is braided and the case where the braiding is symmetric. We prove the functoriality of the cohomologies with respect to weak morphisms of crossed-modules and also prove the "long" exact cohomology sequence associated to a short exact sequence of crossed-modules and weak morphisms.

On the nonabelian cohomology with coefficients in a crossed module

This paper is concerned with the nonabelian cohomology of groups with coefficients in crossed modules. These objects were introduced by Dedecker and studied by Breen, Borovoi, Noohi and many others. In this paper we study several important objects that are classified by these cohomologies and for them we develop a theory similar to the Schreier obstruction theory of group extensions.

Crossed interval groups and operations on the Hochschild cohomology

We prove that the operad B of natural operations on the Hochschild cohomology has the homotopy type of the operad of singular chains on the little disks operad. To achieve this goal, we introduce crossed interval groups and show that B is a certain crossed interval extension of an operad T whose homotopy type is known. This completes the investigation of the algebraic structure on the Hochschild cochain complex that has lasted for several decades.