Generalized crossed products applied to maximal orders, Brauer groups and related exact sequences
نویسندگان
چکیده
منابع مشابه
Crossed complexes, free crossed resolutions and graph products of groups
The category of crossed complexes gives an algebraic model of CW -complexes and cellular maps. Free crossed resolutions of groups contain information on a presentation of the group as well as higher homological information. We relate this to the problem of calculating non-abelian extensions. We show how the strong properties of this category allow for the computation of free crossed resolutions...
متن کاملMaximal Crossed Product Orders over Discrete Valuation Rings
The problem of determining when a (classical) crossed product T = S ∗ G of a finite group G over a discrete valuation ring S is a maximal order, was answered in the 1960’s for the case where S is tamely ramified over the subring of invariants S. The answer was given in terms of the conductor subgroup (with respect to f) of the inertia. In this paper we solve this problem in general when S/S is ...
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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, ...
متن کاملBrauer Groups
I define the Brauer group of a field k as similarity classes of central simple algebras over k. Then I introduce non-abelean cohomology and use it to prove that the Brauer group is isomorphic to a certain cohomology group. Brauer groups show up in global class field theory.
متن کاملExpanders, Exact Crossed Products, and the Baum-connes Conjecture
Abstract. We reformulate the Baum-Connes conjecture with coe cients by introducing a new crossed product functor for C⇤-algebras. All confirming examples for the original Baum-Connes conjecture remain confirming examples for the reformulated conjecture, and at present there are no known counterexamples to the reformulated conjecture. Moreover, some of the known expander-based counterexamples to...
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ژورنال
عنوان ژورنال: Journal of Pure and Applied Algebra
سال: 1984
ISSN: 0022-4049
DOI: 10.1016/0022-4049(84)90002-1