A C∞-Hopf algebra is a C∞-algebra which is also a convenient Hopf algebra with respect to the structure induced by the evaluations of smooth functions. We characterize those C∞-Hopf algebras which are given by the algebra C∞(G) of smooth functions on some compact Lie group G, thus obtaining an anti-isomorphism of the category of compact Lie groups with a subcategory of convenient Hopf algebras.

A new C*-enlargement of a C*-algebra A nested between the local multiplier algebra Mloc(A) of A and its injective envelope I(A) is introduced. Various aspects of this maximal C*-algebra of quotients, Qmax(A), are studied, notably in the setting of AW*algebras. As a by-product we obtain a new example of a type I C*-algebra A such that Mloc(Mloc(A)) 6= Mloc(A).

We study the ideal structure of C∗-algebras arising from C∗-correspondences. We prove that gauge-invariant ideals of our C∗-algebras are parameterized by certain pairs of ideals of original C∗-algebras. We show that our C∗-algebras have a nice property which should be possessed by generalization of crossed products. Applications to crossed products by Hilbert C∗-bimodules and relative Cuntz-Pim...

To a directed graph E is associated a C∗-algebra C∗(E) called a graph C∗algebra. There is a canonical action γ of T on C∗(E), called the gauge action. In this paper we present necessary and sufficient conditions for the fixed point algebra C(E) to be simple. Our results also yield some structure theorems for simple graph algebras.

We study the ideal structure of C∗-algebras arising from C∗-correspondences. We prove that gauge-invariant ideals of our C∗-algebras are parameterized by certain pairs of ideals of original C∗-algebras. We show that our C∗-algebras have a nice property which should be possessed by generalization of crossed products. Applications to crossed products by Hilbert C∗-bimodules and relative Cuntz-Pim...

We study actions of “compact quantum groups” on “finite quantum spaces”. According to Woronowicz and to general C-algebra philosophy these correspond to certain coactions v : A → A ⊗ H . Here A is a finite dimensional C-algebra, and H is a certain special type of Hopf ∗-algebra. If v preserves a positive linear form φ : A → C, a version of Jones’ “basic construction” applies. This produces a ce...

We study residually finite-dimensional (or RFD) operator algebras which may not be self-adjoint. An algebra RFD while simultaneously possessing completely isometric representations whose generating C⁎-algebra is RFD. This has provided many hurdles in characterizing residual finite-dimensionality for algebras. To better understand the elusive behavior, we explore C⁎-covers of an algebra. First, ...

We develop a complete theory of non-formal deformation quantization on the cotangent bundle weakly exponential Lie group. An appropriate integral formula for star-product is introduced together with suitable space functions which well defined. This becomes Fréchet algebra as pre-C*-algebra. Basic properties are proved, and extension to Hilbert an distributions given. A C*-algebra observables st...

In this paper, we extend the constructions of Boava and Exel to present C∗-algebra associated with an injective endomorphism a group finite cokernel as partial algebra consequently crossed product. With representation, another way study such C∗-algebras, only using tools from products.

The present paper is devoted to infinite order decompositions of C*-algebras. It is proved that an infinite order decomposition (IOD) of a C*-algebra forms the complexification of an order unit space, and, if the C*-algebra is monotone complete (not necessarily weakly closed) then its IOD is also monotone complete ordered vector space. Also it is established that an IOD of a C*-algebra is a C*-...