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nuclear C*-algebra (Definition)
Definition 0.1   A C*-algebra $A$ is called a nuclear C*-algebra if all C*-norms on every algebraic tensor product $A \otimes X$ , of $A$ with any other C*-algebra $X$ , agree with, and also equal the spatial C*-norm (viz Lance, 1981). Therefore, there is a unique completion of $A \otimes X$ to a C*-algebra , for any other C*-algebra $X$ .

Examples of nuclear C*-algebras

Exact C*-algebra

In general terms, a $C^*$ -algebra is exact if it is isomorphic with a $C^*$ -subalgebra of some nuclear $C^*$ -algebra. The precise definition of an exact $C^*$ -algebra follows.
Definition 0.2   Let $M_n$ be a matrix space, let $\mathcal{A}$ be a general operator space, and also let $\mathbb{C}$ be a C*-algebra. A $C^*$ -algebra $\mathbb{C}$ is exact if it is `finitely representable' in $M_n$ , that is, if for every finite dimensional subspace $E$ in $\mathcal{A}$ and quantity $epsilon > 0$ , there exists a subspace $F$ of some $M_n$ , and also a linear isomorphism $T:E \to F$ such that the $cb$ -norm $$|T|_{cb}|T^{-1}|_{cb} < 1 + epsilon.$$

Note: A counter-example

A $C^*$ -subalgebra of a nuclear C*-algebra need not be nuclear.

Bibliography

1
E. C. Lance. 1981. Tensor Products and nuclear C*-algebras., in Operator Algebras and Applications, R.V. Kadison, ed., Proceed. Symp. Pure Maths., 38: 379-399, part 1.
2
N. P. Landsman. 1998. ``Lecture notes on $C^*$ -algebras, Hilbert $C^*$ -Modules and Quantum Mechanics", pp. 89 a graduate level preprint discussing general C*-algebras in Postscript format.




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See Also: quantum operator algebras in quantum field theories, noncommutative geometry, groupoid C*-convolution algebras, groupoid C*-dynamical system, compact quantum groupoids related to C*-algebras, $C^*$-algebra, quotients in $C^*$-algebras

Other names:  quantum operator algebra, C*-algebra, $C^*$-algebra
Also defines:  generated C*-algebra, exact C^*-algebra
Keywords:  quantum operator algebra, nuclear C*-algebra, generators
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Cross-references: linear isomorphism, subspace, finite dimensional, representable, operator, matrix, isomorphic, terms, type, discrete, amenable, products, amenable groups, group, finite-dimensional, commutative, completion, viz, tensor product, algebraic, C*-norms, nuclear
There are 13 references to this entry.

This is version 58 of nuclear C*-algebra, born on 2008-07-14, modified 2009-02-02.
Object id is 10787, canonical name is NuclearCAlgebra.
Accessed 2618 times total.

Classification:
AMS MSC81R15 (Quantum theory :: Groups and algebras in quantum theory :: Operator algebra methods)
 81R50 (Quantum theory :: Groups and algebras in quantum theory :: Quantum groups and related algebraic methods)
 81T05 (Quantum theory :: Quantum field theory; related classical field theories :: Axiomatic quantum field theory; operator algebras)

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