c_star_algebra m21k C-Star-algebras are an important area of research in functional_analysis. A C*-algebra can be defined concretely as a complex algebra A of linear operators on a complex Hilbert_space:- A is a topologically closed_set in the norm_topology of operators. A is closed under the operation taking adjoints of operators. It is generally believed that C*-algebras were first considered primarily for their use in quantum_mechanics to model algebras of physical observables . This line of research began in an extremely rudimentary form with Heisenberg"'s matrix_mechanics and in a more mathematically developed form with P. Jordan around 1933. Subsequently von_Neumann attempted to establish a general framework for these algebras which culminated in a series of papers on rings of operators. These papers considered a special class of C*-algebras which are now known as "von_Neumann algebras". Around 1943, the work of Gelfand, Naimark and Segal yielded an abstract characterisation of C*-algebras making no reference to operators. C*-algebras are now an important tool in the theory of unitary representations of locally compact groups, and are also used in algebraic formulations of quantum_mechanics. 041009 ... . http://encyclopedia.thefreedictionary.com/C-star-algebra 041009 ... dudeinanigloo Well thank you for that. Some people here don't even know what algebra is. 041009 ... gemaniacal I can adjoint an operator *nodding vigorously* yes I can 041221 what's it to you? who go blather from