in this paper we introduce a new definition of the first non-abelian cohomology of topological groups.  we relate the cohomology of a normal subgroup $n$ of a topological group $g$ and the quotient $g/n$ to the cohomology of $g$. we get the inflation-restriction exact sequence. also, we obtain a seven-term exact cohomology sequence up to dimension 2. we give an interpretation of the first non-a...

–a notion of amenability for topological semigroups is introduced. a topological semigroup s iscalled johnson amenable if for every banach s -bimodule e , every bounded crossed homomorphism froms to e* is principal. in this paper it is shown that a discrete semigroup s is johnson amenable if and only if1(s) is an amenable banach algebra. also, we show that if a topological semigroup s is johns...

In this paper we introduce a new definition of the first non-abelian cohomology of topological groups.  We relate the cohomology of a normal subgroup $N$ of a topological group $G$ and the quotient $G/N$ to the cohomology of $G$. We get the inflation-restriction exact sequence. Also, we obtain a seven-term exact cohomology sequence up to dimension 2. We give an interpretation of the first non-a...

Mansfield showed how to induce representations of crossed products of C∗algebras by coactions from crossed products by quotient groups and proved an imprimitivity theorem characterising these induced representations. We give an alternative construction of his bimodule in the case of dual coactions, based on the symmetric imprimitivity theorem of the third author; this provides a more workable w...

For a maximal coaction δ of a discrete group G on a C-algebra A and a normal subgroup N of G, there are at least three natural A ×δ G δ̂| N − A ×δ| G/N imprimitivity bimodules: Mansfield’s bimodule Y G G/N(A); the bimodule assembled by Ng from Green’s A ×δ G δ̂ G ׈̂ δ| G/N − A ×δ G δ̂| N imprimitivity bimodule X N (A ×δ G) and Katayama duality; and the bimodule assembled from X G N (A ×δ G) and th...

We construct the crossed product of a C(X)-algebra by an endomorphism, in such a way that it becomes induced by a Hilbert C(X)-bimodule. Furthermore we introduce the notion of C(X)-category, and discuss relationships with crossed products and duality for compact groups.

Let U , V , and W be multiplicative unitaries coming from discrete Kac systems such that W is an amenable normal submultiplica-tive unitary of V with quotient U. We define notions for right-Hilbert bimodules of coactions of SV andˆSV , their restrictions to SW andˆSU , their dual coactions, and their full and reduced crossed products. If N (A) denotes the imprimitivity bimodule associated to a ...

A continuous one-parameter group of unitary isometries of a right-Hilbert C*bimodule induces a quasi-free dynamics on the Cuntz-Pimsner C*-algebra of the bimodule and on its Toeplitz extension. The restriction of such a dynamics to the algebra of coefficients of the bimodule is trivial, and the corresponding KMS states of the Toeplitz-Cuntz-Pimsner and Cuntz-Pimsner C*-algebras are characterize...

We set up a fibred categorical theory of obstruction and classification morphisms that specialises to the one monoidal functors between groups also Schreier-Mac Lane group extensions. Further applications are provided crossed extensions bimodule butterflies, with in particular non-abelian unital associative algebras terms Hochschild cohomology.

Let $A$ be a Banach algebra and $X$ be a Banach $A$-bimodule with the left and right module actions $pi_ell: Atimes Xrightarrow X$ and $pi_r: Xtimes Arightarrow X$, respectively. In this paper, we  study  the topological centers of the left module action $pi_{ell_n}: Atimes X^{(n)}rightarrow X^{(n)}$ and the right module action $pi_{r_n}:X^{(n)}times Arightarrow X^{(n)}$,  which inherit from th...