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

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

The prolongation of central extensions

The aim of this paper is to study the $(alpha, gamma)$-prolongation of central extensions. We obtain the obstruction theory for $(alpha, gamma)$-prolongations and classify $(alpha, gamma)$-prolongations thanks to low-dimensional cohomology groups of groups.

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.

Strict Gr-categories and applications on classification of extensions of groups of the type of a crossed module

In this paper we state some applications of Gr-category theory on the classification of crossed modules and on the classification of extensions of groups of the type of a crossed module.