منابع مشابه
Crossed Products of Operator Algebras: Applications of Takai Duality
Let (G,Σ) be an ordered abelian group with Haar measure μ, let (A,G, α) be a dynamical system and let A oα Σ be the associated semicrossed product. Using Takai duality we establish a stable isomorphism Aoα Σ ∼s ( A⊗K(G,Σ, μ) ) oα⊗Ad ρ G, where K(G,Σ, μ) denotes the compact operators in the CSL algebra AlgL(G,Σ, μ) and ρ denotes the right regular representation of G. We also show that there exis...
متن کاملDiscrete Product Systems and Twisted Crossed Products by Semigroups
A product system E over a semigroup P is a family of Hilbert spaces {Es : s ∈ P} together with multiplications Es×Et → Est. We view E as a unitary-valued cocycle on P , and consider twisted crossed products A⋊β,EP involving E and an action β of P by endomorphisms of a C∗-algebra A. When P is quasi-lattice ordered in the sense of Nica, we isolate a class of covariant representations of E, and co...
متن کاملSkew Products and Crossed Products by Coactions
Given a labeling c of the edges of a directed graph E by elements of a discrete group G, one can form a skew-product graph E ×c G. We show, using the universal properties of the various constructions involved, that there is a coaction δ of G on C∗(E) such that C∗(E ×c G) is isomorphic to the crossed product C ∗(E) ×δ G. This isomorphism is equivariant for the dual action δ̂ and a natural action ...
متن کاملCrossed 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 کاملCrossed Products by a Coalgebra
We introduce the notion of a crossed product of an algebra by a coalgebra C, which generalises the notion of a crossed product by a bialgebra well-studied in the theory of Hopf algebras. The result of such a crossed product is an algebra which is also a right C-comodule. We find the necessary and sufficient conditions for two coalgebra crossed products be equivalent. We show that the two-dimens...
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ژورنال
عنوان ژورنال: Journal of Functional Analysis
سال: 2019
ISSN: 0022-1236
DOI: 10.1016/j.jfa.2018.11.017