in this work we deal with actions of vector groupoid which is a new concept in the literature‎. ‎after we give the definition of the action of a vector groupoid on a vector space‎, ‎we obtain some results related to actions of vector groupoids‎. ‎we also apply some characterizations of the category and groupoid theory to vector groupoids‎. ‎as the second part of the work‎, ‎we define the notion...

Using free simplicial groups, it is shown how to construct a free or totally free 2-crossed module on suitable construction data. 2-crossed complexes are introduced and similar freeness results for these are discussed.

Using free simplicial groups, it is shown how to construct a free or totally free 2-crossed module on suitable construction data. 2-crossed complexes are introduced and similar freeness results for these are discussed.

We prove, under some mild conditions, that the equivariant twisted K-theory group of a crossed module admits a ring structure if the twisting 2-cocycle is 2multiplicative. We also give an explicit construction of the transgression map T1 : H ∗(Γ • ;A) → H((N ⋊ Γ) • ;A) for any crossed module N → Γ and prove that any element in the image is ∞-multiplicative. As a consequence, we prove that, unde...

The classifying space of a crossed complex generalises the construction of Eilenberg-Mac Lane spaces. We show how the theory of fibrations of crossed complexes allows the analysis of homotopy classes of maps from a free crossed complex to such a classifying space. This gives results on the homotopy classification of maps from a CW -complex to the classifying space of a crossed module and also, ...

Results on the niteness of induced crossed modules are proved both algebraically and topologically Using the Van Kampen type theorem for the fundamen tal crossed module applications are given to the types of mapping cones of classifying spaces of groups Calculations of the cohomology classes of some nite crossed modules are given using crossed complex methods Introduction Crossed modules were i...