Search results for "Homological algebra"
showing 2 items of 2 documents
Construction of Fibred Categories
2019
In Section 5, we introduce methods from classical homological algebra (i.e. using mostly the language of derived categories of abelian categories and their Verdier quotients) to construct the main examples of premotivic categories of interest in this book, while, in Section 6, we study how to check that the localization axiom holds in practice. Section 7 is devoted to the process of obtaining new fibred categories from old ones, by considering homotopy theoretic modules over a ring object.
Commuting powers and exterior degree of finite groups
2011
In [P. Niroomand, R. Rezaei, On the exterior degree of finite groups, Comm. Algebra 39 (2011), 335-343] it is introduced a group invariant, related to the number of elements $x$ and $y$ of a finite group $G$, such that $x \wedge y = 1_{G \wedge G}$ in the exterior square $G \wedge G$ of $G$. This number gives restrictions on the Schur multiplier of $G$ and, consequently, large classes of groups can be described. In the present paper we generalize the previous investigations on the topic, focusing on the number of elements of the form $h^m \wedge k$ of $H \wedge K$ such that $h^m \wedge k = 1_{H \wedge K}$, where $m \ge 1$ and $H$ and $K$ are arbitrary subgroups of $G$.