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C*-algebra

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Also known as B*-algebra, †-algebra

In mathematics, specifically in functional analysis, a C∗-algebra (pronounced "C-star") is a Banach algebra together with an involution satisfying the properties of the adjoint. A particular case is that of a complex algebra A of continuous linear operators on a complex Hilbert space with two additional properties:

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Article

17 sections
Contents
  • Abstract characterization
  • History: B*-algebras and C*-algebras
  • Structure of C*-algebras
  • Self-adjoint elements
  • Quotients and approximate identities
  • Examples
  • Finite-dimensional C*-algebras
  • C*-algebras of operators
  • C*-algebras of compact operators
  • Commutative C*-algebras
  • C*-enveloping algebra
  • Von Neumann algebras
  • Type for C*-algebras
  • C*-algebras and quantum field theory
  • See also
  • Notes
  • References

In mathematics, specifically in functional analysis, a C∗-algebra (pronounced "C-star") is a Banach algebra together with an involution satisfying the properties of the adjoint. A particular case is that of a complex algebra A of continuous linear operators on a complex Hilbert space with two additional properties: A is a topologically closed set in the norm topology of operators. A is closed under the operation of taking adjoints of operators.

Another important class of non-Hilbert C*-algebras includes the algebra C_0(X) of complex-valued continuous functions on X that vanish at infinity, where X is a locally compact Hausdorff space.

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